Question

an isosceles right triangle is always a 45-45-90 triangle.
a. true
b. false

Explanation:

In an isosceles right - triangle, one angle is 90 degrees. Since it is isosceles, the other two angles are equal. Using the angle - sum property of a triangle (sum of angles in a triangle is 180 degrees), if the equal angles are $x$ each, then $x + x+90 = 180$. Solving for $x$ gives $2x=90$, so $x = 45$ degrees. So it is a 45 - 45 - 90 triangle.

Answer:

A. True