Question

1. solve for x

setup:
x=

Explanation:

Step1: Identify the triangle type

Since all side - lengths of $\triangle DEF$ are 5 (i.e., $DE = EF=DF = 5$), $\triangle DEF$ is an equilateral triangle.

Step2: Recall the angle - property of an equilateral triangle

In an equilateral triangle, each interior angle is 60°. So, $3x=60$.

Step3: Solve for x

Divide both sides of the equation $3x = 60$ by 3. We get $x=\frac{60}{3}$.

Answer:

Setup: $3x = 60$
$x = 20$