# Solution to #1-1

Paper 1 Difficulty: Easy

The radius of a sphere is r=12.37 m. What is the volume of the sphere correct to two significant figures?
A) $7928.62 \ \textrm{m}^{3}$
B) $7920 \ \textrm{m}^{3}$
C) $7928 \ \textrm{m}^{3}$
D) $7900 \ \textrm{m}^{3}$

[Maximum mark: 1]

$V=\frac{4}{3} \pi r^{3}\ V=7928.62 \ \textrm{m}^{3}$
The significant figures are digits of a number that carry meaning. In this case, the first two digits of the number carrying meaning are 7 and 9, so the answer is $7900 \ \textrm{m}^{3}$.