I don’t understand what I have to do

over 90° = obtuse angle

less than 90° = acute angle

two angles next to eachother on the same flat line are a+b=180

so angle 1 is 180-135=45

There are different types of angles. They are as follows:

1) Acute angle - less than 90 degrees

2) Right angle - exactly 90 degrees

3) Obtuse angle - greater than 90 degrees but less than 180 degrees

4) Straight angle - exactly 180 degrees

5) Reflex angle - greater than 180 degrees

In part 1 they want you to identify what kind of angle is shown

Number 1 is 135 degrees

-It is not less than 90 degrees so it cannot be an Acute angle

-It is not exactly 90 degrees so it cannot be a Right angle

-It is not exactly 180 degrees so it cannot be a Straight angle

-It is not greater than 180 degrees so it cannot be a Reflex angle

-It is greater than 90 degrees and less than 180 degrees so it is in fact an Obtuse angle

For part 2 they want you to calculate the value of the missing angle

A straight line has 180 degrees so we can find the value of the missing angle by subtracting  135 degrees from 180 degrees

180 - 135 = 45

The missing angle is 45 degrees which is an Acute angle because it is less than 90 degrees

the answer would be 0.54