A more accurate answer, when calculating circle-based objects, can be obtained by not using a value of π, but to leave it as a constant.
Questions may ask for the answer to be given in terms of π. In this instance, do not use a value for π, show the answer instead as a multiple of π.
1. A circle has a radius of 8 cm. What is the area of the circle? Give your answer in terms of π.
Answer: 64π cm2
Area of a circle ` = pir^2`
`A = pi xx 8^2`
`A = 64pi` cm2 (answer in terms of π)
2. A deep underwater sphere to explore the bottom of the ocean has a diameter of 3m. What is the volume of the sphere? Give your answer in terms of π.
Answer: 4.5π m3
Volume of sphere `= frac(4)(3)pir^3`
`V = frac(4)(3) xx pi xx (frac(3)(2))^3` (change diameter to radius)
`V = 4.5pi` m3