I'm asked to find the circumference of a circle to the nearest tenth and the area of the same circle to the nearest hundredth. The circle has a diameter of 30 and a radius of 15. I got a circumference of 94.2 and an area of 188.48cm2 with these formulas: C=2piR and A=piR2.
Is this correct?
No, not hardly
Do the area (paste this into your google search window)
PI*15^2
Then the circ..
PI*30
and you were right on that.
The circumference looks good, but you may want to check the area calculations. (15^2 = 225)
Yes, your formulas and calculations are correct.
Yes, your calculations are correct for finding the circumference and area of a circle with a diameter of 30 and a radius of 15.
To find the circumference of a circle, you can use the formula C = 2πR, where C is the circumference and R is the radius. In this case, the radius is 15:
C = 2π × 15
C = 30π
Now, to find the value of C to the nearest tenth, you need to use an approximation for the value of π, which is approximately 3.14159. So:
C ≈ 30 × 3.14159
C ≈ 94.24875
Rounded to the nearest tenth, the circumference is 94.2.
To calculate the area of a circle, you can use the formula A = πR^2, where A is the area and R is the radius. In this case, the radius is 15:
A = π × 15^2
A = π × 225
Again, you can approximate π to 3.14159:
A ≈ 3.14159 × 225
A ≈ 706.85875
Rounded to the nearest hundredth, the area is 706.86 cm².
Therefore, your calculated values of the circumference and area are correct: the circumference is approximately 94.2 (to the nearest tenth) and the area is approximately 706.86 cm² (to the nearest hundredth).