What is m∠a?

a.
20°

b.
60°

c.
80°

d.
100°

Simple,

look at the picture, you can tell it is an acute angle, or less than 90 degrees.

This being said, you know your answer has to be less than 90 (<90)

One line goes through 80, and the other goes through 20...

How to find the angle?

80-20=

=60

Now, is this number smaller than 90 as we stated earlier? It is, thus,

your answer is m<A=60  (B)