How do you prove that a triangle is right angled?

Question

what equations/stuff do you have to do to prove it is a right angle triangle?

thanks

yes...i know it needs to be 90 degrees lol.
my brother is in gr. 10 math and i dont remember but he needs to find slopes..or something..

Answer 1

Let sides be of length a , b , c, where c is the longest side.
If right angled triangle:-
c² = a² + b²

Answer 2

You can use the Pythagorean theorem. If the length of the longest side squared is equal to the square of other two sides, it is a right triangle.

For example, if someone told you that a triangle had sides of 5, 12 and 13, you would check to see if:

5² + 12² =? 13²
25 + 144 =? 169
169 = 169

So yes, 5-12-13 makes a right triangle.

Now try another example of a triangle with sides 6, 8, 9:
6² + 8² =? 9²
36 + 64 =? 81
100 =? 81
100 ≠ 81

So 6-8-9 would *not* be a right triangle.

Answer 3

It depends what you know about the triangle. If you have two angles then if they add up to 90, the third will add up to 180. If you have three sides then you can use pythagoras' theorem to prove that a^2 + b^2 = c^2. If you are given a combination of sides and angles it complicates it (sin/cosine rule etc.) but it is the same idea.

Answer 4

If 2 of the angles add up to 90 degrees.
.

Answer 5

It depends on what you are given. If you are given lengths of sides, you can use the pythagorean theorem (a^2 + b^2 = c^2) and see if it works out. If you are given angles, then one of them must be 90 degrees. If you are given a combination, you may need to use the law of sines and/or cosines to find the lengths of the sides to see if they satisfy the pythagorean theorem.

Answer 6

If two of the angles add up to 90 degrees.

If the square on the hypotenuse is equal to the sum of the squares on the other two sides

Answer 7

I learned that even if the angle isnt completely 90 degrees, you should put the box symol in to show the 90 degree angle.


Angle and side of one angle should look like this
l
l_
l_l_____

Answer 8

you ought to purpose Pythagoras' theorem, even however your preliminary plan to apply scalar dot product is possibly the quickest technique and would not require a calculator. i attempted this issue and located that for the coordinates given, this is in certainty a suitable angled triangle with vectors BA and AC producing 0 with the dot product. bear in mind that however the scalar dot product produces a scalar consequence, it fairly is a function operated on 2 VECTORS, so which you cant in simple terms use A,B or C as those are coordinates. you ought to do A-B for vector BA, C-A for vector AC.

Answer 9

if it satisfies the pythagorean theorem.