Which one makes a right triangle?

Explanation:

As mentioned earlier (in a previous post) the triangle with sides 2,5,7 is not a right triangle. So we can rule out choice A.

For choice B, we have a = 6, b = 8, c = 10, and that leads to...

a^2+b^2 = c^2

6^2+8^2 = 10^2

36+64 = 100

100 = 100

The true equation at the end means the beginning equation is true as well for those a,b,c values. Therefore, we have a right triangle and the answer is choice B

Choices C and D are similar to choice A. They make a^2+b^2 = c^2 to be false.

60°

step-by-step explanation:

the measure angle of c in an isosceles triangle abc is 60° because in isosceles triangle,the measures of all the angles is 60°.