Question

$\large{The curved surface area of a cone is 4070cm^2,and its diameter is 70 cm. What is its slant height?}$

$\color{indigo}{please}$

Answer 1

The total surface area is the sum of its area of its base and side (lateral) surface.
The side(lateral) surface area of the cone is the area of side surface only.
The cone surface area is given by the following formula:
S=
$\pi \times {r }^{2} +\pi \times r \times l$
where,
l is the slant height of the cone.
r is the radius of the cone.
We have the following data:
Diameter=70cm
Surface Area=4070cm^2
Slant height=?
We neet to find the radius first:
$diameter = \frac{r}{2}$
so diameter is=
$\frac{70}{2} = 35cm$

so the slant height l would be
$l = \frac{4070}{35 \times \pi } - 35$
$l = 2.01489cm$

Answer 2

Answer:

37 cm

Step-by-step explanation:

Given, Diameter of cone = 70 cm.

Then, radius = 35 cm.

Given, Curved surface area of cone = 4070 cm².

πrl = 4070

(22/7) * 35 * l = 4070

110 * l = 4070

l = 4070/110

l = 37 cm.

Therefore, Slant height = 37 cm.

Hope it helps!