Jambmaths question:
Find the radius of a sphere whose surface area is 154 cm2 [Take $\pi =\tfrac{22}{7}$]
Option A:
7.00cm
Option B:
3.50cm
Option C:
3.00cm
Option D:
1.75cm
Jamb Maths Solution:
$\begin{align} & Surface\text{ }area\text{ }of\text{ }a\text{ }sphere~=A=4\pi {{r}^{2}} \\ & A=4\pi {{r}^{2}} \\ & 154=4\times \tfrac{22}{7}\times {{r}^{2}} \\ & {{r}^{2}}=\frac{154\times 7}{4\times 22}=\frac{49}{4} \\ & r=\sqrt{\frac{49}{4}}=\frac{7}{2}=3.50cm \\\end{align}$
Jamb Maths Topic:
Year of Exam: