Question

calculate the area of a circular disc 0.86m in diameter. (π=3.142)

Answer 1

The area $A$ of a circular disk with diameter $d$ is

$$A=\dfrac{\pi\cdot d^2 }{4}$$

The area of a circular disc 0.86m in diameter is

$$A=\dfrac{\pi\cdot(0.86m)^2}{4}=0.1849\pi m^2\approx0.5809558m^2$$

The area of a circular disc 0.86m in diameter is $0.5809558m^2.$