Practicing Success

Target Exam

CUET

Subject

-- Mathematics - Section B1

Chapter

Application of Integrals

Question:

The area of the base of a cone is 616 sq. cm. Its height is 48 cm. Find its total surface area.

Options:

2816 cm2

2861 cm2

2618 cm2

2681 cm2

Correct Answer:

2816 cm2

Explanation:

We know the base of a cone is circular

Then, area of circle = πr2 = 616

$⇒r^2=\frac{616×7}{22}=196$ ⇒ r = 14 cm

Also, total surface area of a cone = πr(r + l)

Where ‘r’ is the radius of cone and ‘l’ is the slant height

For a cone slant height = $l=\sqrt{r^2+h^2}$

$l=\sqrt{48^2+14^2}=\sqrt{2500}=50$

∴  Total surface area = $\frac{22}{7}×14×(14+50)=2816cm^2$