Question

problem 17: (first taught in lesson 42) find x. after you enter your answer press go. x =

Explanation:

Step1: Identify isosceles triangle

The triangle has two equal - side markings, so it is isosceles. The base - angles of an isosceles triangle are equal.

Step2: Use angle - sum property of a triangle

The sum of interior angles of a triangle is $180^{\circ}$. Let the base - angles be $y$. We know one angle is $36^{\circ}$, so $x + y+y=180^{\circ}$. Since $y = 36^{\circ}$, then $x+2\times36^{\circ}=180^{\circ}$.

Step3: Solve for $x$

$x=180^{\circ}- 72^{\circ}=72^{\circ}$.

Answer:

$72$