Answer:
1. r=5 C=31.4 A=78.5
2. D=18 C=56.52 A=254.34
3. D=38 C=119.32 A=1133.54
4. D=4 C=12.56 A=12.56
5. r=15 C=94.2 A=706.5
6. D=34 C=106.76 A=907.46
For 7, I couldn't tell if the given Diameter was 8 or 6 so I did both. If it is an 8, then r = 4, C=25.12, and A=50.24; If it is a 6, then r = 3, C=18.84, and A=28.26
8. r=10 C=62.8 A=314
9. D=32 C=100.48 A=803.84
Explanation:
Radius is always half the diameter, and the Diameter is always twice the Radius. For example, number 1, it tells you the Diameter is 10, so the Radius is 5 (10/2=5). And on 2, it tells you the radius is 9, so the Diameter is 18 (9x2=18).
The top of your paper has the equations for both Circumference and Area of a circle. To show you how to properly input those numbers, I'll use number 1 again as example.
For Circumference, it tells you the equation is πD. That means that Circumference is 3.14 (which is what they say to use as π) times the Diameter. So we know the Diameter is 10, so we have 3.15 times 10 which gives you 31.4.
For Area, it tells you the equation is π
. That means the Area is 3.14 times the Radius to the power of 2. Because we know what the radius is 5 from before, we can input it as such, 3.14 times
. In the end, that gives you 78.5.
If you have any other questions, feel free to ask :) Hope this helped!