CPM Homework Help : MC1 Problem 5-18

Estimate the measure of each angle below. Then describe each angle as acute angle (measures between $0^\circ$ and $90^\circ$ ), right angle (measures $90^\circ$ ), or obtuse angle (measures between $90^\circ$ and $180^\circ$ )

Hint (a):
The corner of your book is a right angle. Do you think this angle is bigger or smaller than the angle at the corner of your book? About how many of these angles could you put in the corner of your book?
Answer (a):
This angle is approximately $40°$ .

Hint (b):
Do you think this angle is bigger than the angle at the corner of your book? About how much bigger is it?
Answer (b):
This angle is approximately $100°$ .

Hint (c):
A square in an angle means that the angle is $90°$ .

Hint (d):
How does this angle compare to the angles in parts(a), (b), and (c)? If it is bigger, how much bigger? If it is smaller, how much smaller?