7th Grade IXL Homework: Circumference and Area of Circles PDF

## SLT 2a: - I can determine the relationship between circumference and area of circles ### Today You Will Need: - Pencil - Calculator - New Notes ### IXL Homework - Expectation - 5 Skills per week - Goal - Smart Score of 80 - OR - - 15 minutes per night if you cannot get to 80. -...

## SLT 2a: - I can determine the relationship between circumference and area of circles ### Today You Will Need: - Pencil - Calculator - New Notes ### IXL Homework - Expectation - 5 Skills per week - Goal - Smart Score of 80 - OR - - 15 minutes per night if you cannot get to 80. - Grade - 10 points per week ### DEADLINE: Sunday PM ### MAP - M: Tuesday! ## 7th Grade IXL Homework - 7th (S.13) Identify equivalent linear expressions II KAR - 7th (T.9) Solve two-step equations QEB - 7th (T.11) Choose two-step equations: word problems 8NH - 7th (U.1) Solutions to inequalities 8BA - 7th Solve two-step inequalities HXG ### Not Finished - Period 1: Calvin, Derek, Eric - Period 2: Ian B., Julio, Leslie, Emily Q. - Period 7: Luka - Period 8: Trentyn, Ben, Kaitlyn, Jason, Chris ## What is a circle? - A circle is a shape that is perfectly round. - **Area formula:** $πr^2$ - **Circumference formula:** $C=πd$ or $C=2πr$ ### Diagram of a circle - The diagram shows that the circle's circumference is equal to the base of a parallelogram. - The height of the parallelogram is equal to the circle's radius. - The ratio representing the area of the parallelogram is $\frac{1}{2} \times Circumference \times Radius$. - The area of the circle is equal to $πr^2$ since the base of the parallelogram is equal to the circumference ($2πr$) and the height is equal to the radius ($r$). ## Calculate the circumference and area of each circle with the following dimensions: ### a) radius = 4.2 in - **Sketch and label the circle.** - **Circumference** - $C = 2πr$ - $C = 2(3.14)(4.2)$ - $C = 26.376$ in - **Area** - $A = πr^2$ - $A = 3.14(4.2)^2$ - $A = 55.3896$ in$^2$ ### b) diameter = 5.4 cm - **Sketch and label the circle.** - **Circumference** - $C = πd$ - $C = 3.14 \cdot 5.4$ - $C = 16.956$ cm - **Area** - $A = πr^2$ - $A = 3.14(2.7)^2$ - $A = 22.8906$ cm$^2$ ## Finding the Area of a Circle - Find the area of each. **Round to the nearest tenth.** | Circle | Radius | Area | Circumference | |---|---|---|---| | 1 | 12 mi | 452.2 | 75.4 | | 2 | 5.2 km | 84.9 | 32.7 | | 3 | 6.4 mi | 128.6 | 40.2 | | 4 | 3 yd | 28.3 | 18.8 | | 5 | 5 ft | 78.5 | 31.4 | | 6 | 8.6 in | 232.2 | 54 | ## Answer Bank - **32.7** - **31.4** - **18.8** - **28.3** - **78.5** - **40.2** - **232.2** - **54** - **84.9** - **452.2** - **128.6** - **75.4**