# How to find the third coordinate of a triangle

By using our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service. Mathematics Stack Exchange is a question and answer site for people studying math at any level and professionals in related fields. It only takes a minute to sign up. The ambiguity mentioned above can be avoided if you consider ordered angles, i.

We can then solve the problem as follows. You also have all the angles, so you can use the law of sines to find the lengths of all the sides. However, this is not enough. Find an intersection of two lines. If you know the lengths AC and BC from the law of sines or something similarany of the two expressions will do just fine. This procedure actually derives the law of sines. However, using the same given conditions, we can obtain the second solution. See figure 2. Hence, we say it is possible but the solution is not unique.

Sign up to join this community. The best answers are voted up and rise to the top. Home Questions Tags Users Unanswered. Coordinates of third point in a triangle Ask Question. Asked 5 years, 11 months ago. Active 5 years, 11 months ago.

Viewed 1k times. How can I get the coordinates of point C? Sherif elKhatib Sherif elKhatib 5 5 bronze badges.I have 2 points on a graphandand I am wondering how, if it's even possible, to get the third vertex for an equilateral triangle.

I have found the distance of the line, the slope, the perpendicular slope, the height that the triangle is supposed to be, etc. Everything except for the actual third point of the triangle.

Thank you DW, but Ive got that much, I need to know if its possible to get a definite 3rd point with the coordinates from one of the 2 possibilities, and not just guess and check. So sin and cos of So, in short is this even possible, or what other information would i need. If you could explain it as well so i can reciprocate. Update: Thank you DW, but Ive got that much, I need to know if its possible to get a definite 3rd point with the coordinates from one of the 2 possibilities, and not just guess and check.

I don't need exact numbers, just numbers rounded to the nearest integer, by the way. Answer Save. DWRead Lv 7. There are two possible third points. You have two points, Aand B Draw the line segment AB.

Let x be the length of AB. Find the equation of the line that is the perpendicular bisector of AB. Thomas Lv 5. Sin It should be arctan not arcsin. At the beginning. Then the angle between the line from pt A to pt B and the horizontal is The angle between the line from pt A to pt B and the line from pt A to the unknown point is 60 degrees. Therefore the angle between the horizontal and the unknown point is 60 - Still have questions? Get your answers by asking now.By using our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service.

The dark mode beta is finally here. Change your preferences any time. Stack Overflow for Teams is a private, secure spot for you and your coworkers to find and share information. Let's say your result for the third point is C r, s. You need to find D t, wthe symmetrical point of C, with respect to the segment AB. A possible solution, based on a rotation matrix R is:. Learn more. How to find the third coordinate of an equilateral triangle?

Ask Question. Asked 3 years ago. Active 3 years ago. Viewed times. I have the formula for one side, but that cannot give the other one. Need the formula for coordinates of third point on each sides. Subal Roy Subal Roy 1 1 1 bronze badge. For the future, it should be noted that this isn't really a programming question; it's a math question. The Math site would have been a more appropriate place to post. Active Oldest Votes. Since you have the result on one side then it's easy to find the symmetrical point.

Marius D Marius D 33 5 5 bronze badges. Sign up or log in Sign up using Google. Sign up using Facebook. Sign up using Email and Password. Post as a guest Name.

## need help finding 3rd set of coordinates to a right triangle

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With these values, how can i find the coordinates of third point C x,y? Can anyone suggest. I doubt there is a unique answer. Consider seg AB to be a chord in a circle.

All the angles subtended in the major arc will be 30 degrees, if the central angle is So any point on the major arc could be point C for you. For example, if you know the angle at B and the distance BC you could use something like this code samplealthough you will have to replace the distance with an input argument for BC.

Learn more. How to calculate third Coordinate of a triangle, knowing 2 coordinates and 1 angle? Ask Question. Asked 2 years, 11 months ago. Active 1 year, 6 months ago. Viewed times. Vignesh Vignesh 43 4 4 bronze badges. I'm voting to close this question as off-topic because it is not a programming question.

Vignesh You can take this question to math. John If i get the answer i'll use it in my code to return the respective coordinates. Also these type questions are already existing in StackOverflow. Click this Link FYR. Vignesh How is your question not a duplicate of the one you linked to? Just bacuase someone else got one through almost 5 years ago doesn't mean it's right!

I'm voting to close this question as off-topic because it is about Mathematics instead of programming or software development. Active Oldest Votes. Stuti Rastogi Stuti Rastogi 1 1 gold badge 11 11 silver badges 25 25 bronze badges.

It's true for any other angle too. Draw a perpendicular to AB, intersecting anywhere between A and B. Therefore there is a point on this line that gives the angle you want. You need more information. Peet Brits Peet Brits 1, 20 20 silver badges 38 38 bronze badges. Sign up or log in Sign up using Google. Sign up using Facebook.Forums New posts Search forums. What's new New posts Latest activity. Log in Register. Search titles only. Search Advanced search…. New posts. Search forums. Log in. For a better experience, please enable JavaScript in your browser before proceeding.

Thread starter cja Start date Aug 8, Joined Aug 2, Messages DrPhil Senior Member. Joined Nov 29, Messages 1, DrPhil said:. What have you tried? We need to see your work to help where you are stuck. Something in the problem is wrong: the distance between the given points a and b is NOT 0. Do you know how to use slopes to make a line perpendicular to ab, through b?

Subhotosh Khan Super Moderator Staff member. Joined Jun 18, Messages 20, Subhotosh Khan said:. If you don't - that will be the first place to start. If you do - calculate the distance between points A and B. Joined Aug 22, Messages 2, Denis said:.

First, you state that 2 sides are.By using our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service. Mathematics Stack Exchange is a question and answer site for people studying math at any level and professionals in related fields. It only takes a minute to sign up. The three sides, angles and coordinates could be different in the piece of experiment and I am not working with any fix pair of values I am actually dealing with multiple pairs of all above mentioned values.

I need a reliable and accurate way of finding the 3rd coordinate. Currently I have this formula but it calculated two pairs of coordinates forming a butterfly instead of the triangle. As you can see, the coordinate I am trying to get is draw way-off the border of the circle. The coordinate should be found on the border of the circles and not that far away in space. As you might have guessed that I am trying to draw tangents between each circle.

### How to find third coordinate for equilateral triangle on a graph?

I have worked out rest of the code but the coordinate is being calculated incorrectly and thus the right angled triangle is formed incorrectly.

Calculate coordinates of 3rd point vertex of a scalene triangle if angles and sides are known. How to find the third coordinate of a right triangle given 2 coordinates and lengths of each side.

Sign up to join this community. The best answers are voted up and rise to the top. Home Questions Tags Users Unanswered. How to find coordinates of 3rd vertex of a right angled triangle when everything else is known? Ask Question. Asked 5 years, 7 months ago. Active 1 year, 11 months ago. Viewed 17k times. I have: the length of three sides The three angles The other two coordinates of the triangle The triangle can lie in any orientation in 2D coordinate system.By using our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service.

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This is not homework. We are trying to build double connection lines between circles for a project. Point A is x1,y1 and is known. It is the center point of the circle. Point B is x2,y2 and is known. It is the point on the edge of the circle that connects to the center of a remote circle. Point C is unknown x3,y3 and is what we are trying to figure out.

You have much more info than you need to get the answer and it has nothing to do with law of cosine. The law of cosines states that.

We can obtain v1 and v2 by rotating the unit vector from A to B by the angle theta:. Learn more. How to find the 3rd coordinate of a triangle [closed] Ask Question. Asked 7 years, 10 months ago. Active 5 years, 1 month ago. Viewed 5k times. Thanks to anyone who can help! Sean Clark Sean Clark 1, 15 15 silver badges 25 25 bronze badges. Question would probably be more at home at math.

### Triangle calculator VC

Am i right? Active Oldest Votes. Chris Johnson 9, 4 4 gold badges 27 27 silver badges 35 35 bronze badges. So this is where I got caught up earlier. I know algebra fail. I forget how sqrts distribute over terms.