Which could be the measures of the three angles of an acute triangle?

a.
45°, 55°, 80°

b.
35°, 45°, 100°

c.
45°, 45°, 90°

d.
20°, 50°, 110°

All the angles in a triangle must add up to be 180 degrees.  In an acute triangle there cannot be any angles that are 90 degrees or larger. so...

we must simply look for an answer that has no number equal to or larger than 90

answer "A" is the only choice with all three angles under 90 degrees so it is the correct answer

A. is the answer in this question