To measure each angle using the protractor shown in the problems, follow these steps:
1.
Check the Zero Line: Look at where the bottom line of the angle sits on the protractor.
* If the line points to the
right (starts at $0^\circ$ on the right side), you read the numbers on the
inner scale (the smaller numbers going up from right to left).
* If the line points to the
left (starts at $0^\circ$ on the left side), you read the numbers on the
outer scale (the smaller numbers going up from left to right).
2.
Read the Measurement: Follow the other line of the angle up to the curved edge and see which number it crosses.
Here is the step-by-step solution for each problem:
*
Problem 1): The base line is on the right. We use the inner scale. The second line crosses exactly at
60.
*
Problem 2): The base line is on the right. We use the inner scale. The second line crosses exactly at
45 (halfway between 40 and 50).
*
Problem 3): The base line is on the left. We use the outer scale. The second line crosses exactly at
120.
*
Problem 4): The base line is on the right. We use the inner scale. The second line crosses exactly at
70.
*
Problem 5): The base line is on the right. We use the inner scale. The second line goes straight up to
90.
*
Problem 6): The base line is on the left. We use the outer scale. The second line crosses exactly at
150.
*
Problem 7): The base line is on the right. We use the inner scale. The second line crosses exactly at
30.
*
Problem 8): The base line is on the left. We use the outer scale. The second line crosses exactly at
135 (halfway between 130 and 140).
Final Answer:
1) 60°
2) 45°
3) 120°
4) 70°
5) 90°
6) 150°
7) 30°
8) 135°
Parent Tip: Review the logic above to help your child master the concept of using protractor worksheet.
