Grade 7 · Math · Unit 9 of 10
Circle Graphs
Percents and angles of a whole
What your child practises
Reading and building circle graphs: turning percents into numbers of people and sector angles (out of 360°), and comparing categories.
Saskatchewan Curriculum outcome: SP7.2 · circle graphs
How we explain it
Children can open this short lesson before they practise.
- A circle graph shows parts of a whole.
- The whole circle is 100% and 360°.
- Find a part's angle by taking that percent of 360°.
Example: A part of a circle graph is 25%. What angle is it? 25% = 0.25. 0.25 × 360° = 90°. Answer: 90°
Sample questions
A taste of this unit. In the app, questions change every time and get easier or harder to match your child.
Question 1
The table lists the sectors of a circle graph. What percent is missing?
Favourite sport Choice Percent Soccer 25% Hockey 30% Basketball ? Swimming 40% answer box%
Show answer
5 %
Hint: All the sectors add up to 100%. 25 + 30 + 40 = 95, and 100 − 95 = 5%.
Question 2
In a circle graph, how many degrees is the sector for a category that is 10% of the data?
answer box°
Show answer
36 °
Hint: A full circle is 360°. 10% of 360° = 0.1 × 360 = 36°.
Question 3
In a circle graph of survey results, the Fish sector is 40% and stands for 14 students. How many students were surveyed in all?
answer box
Show answer
35
Hint: 40% of the total is 14, so the total is 14 ÷ 0.4 = 35. Check: 40% of 35 = 14.
Question 4
380 students answered this survey. How many more chose Soccer than Hockey?
Favourite sport Choice Percent Soccer 50% Hockey 15% Basketball 5% Swimming 30% answer box
Show answer
133
Hint: Soccer: 50% of 380 = 190. Hockey: 15% of 380 = 57. Difference: 133. (Or 35% of 380.)
Question 5
Why might you choose a circle graph instead of a bar graph?
- To show the order events happened in
- To show amounts that don't make up one whole
- To compare each part with the whole
- To show how something changes over time
Show answer
To compare each part with the whole
Hint: A circle graph's strength is showing what fraction of the whole each category is.
Question 6
In a circle graph, the "Apples" sector has an angle of 306°. What percent of the data does that sector show?
- 306%
- 85%
- 95%
- 15%
Show answer
85%
Hint: Divide by the full turn: 306 ÷ 360 = 0.85 = 85%.