Question

What is the measure of <4?

Answer 1

90°

Explanation:

Two lines intersect each other at a right angle, making them perpendicular. Thus, the resulting angles will all be 90°, making ∠4 = 90°.

Alternatively, we can use the supplementary angles equation.

Let's call the right angle marked in the picture ∠5.

∠4 + ∠5 = 180°, since the line is also a straight angle which measures 180°.

∠4 + 90° = 180°

∠4 = 90°

Either way, ∠4 = 90°

Hope this helps!