Question

The height of the cone is 15 cm If its volume is 1570 cm', then find the

radius of the base (take π = 3.14)​

Answer 1

Solution

Given :-

• Height of cone = 15 cm
• Volume of cone = 1570 cm³

Find :-

• Radius of base cone.

Explanation

Let,

• Radius of base be = r

We Know

★ Volume of cone = πr²h/3

Now, keep all above Values

==> 1570 = 22/7 × r² × 15

==> 1570 × 7 = 22 × 15 × r²

==> (1570 × 7)/(22 × 15) = r²

==> 10,990/330= r²

==> r² =33.30

==> r = √33.30

==> r = 5.8 cm

Hence

• Radius will be of base = 5.8 cm

________________

Answer 2

Given:-

• The height of cone is 15 cm.
• Its volume is 1570 cm³.

To Find:-

• Radius of it's base?

Solution:-

Volume of cone

$\dag { \boxed{ \underline{ \pink{⅓ \times \rm \pi \times {r}^{2} \times h}}}}$

Where,

• r = radius
• h = height

According to the question:-

$↝\frac{1}{3} \times \rm \pi \times {r}^{2} \times h = 1570 \\ \\ ↝ \cancel\frac{1}{3} \times \rm 3.14 \times {r}^{2} \times \cancel{15} = 1570 \\ \\ ↝ 3.14\times {r}^{2} \times 5 = 1570 \\ \\↝ {r}^{2} = \frac{1570}{3.14 \times 5} \\ \\↝ {r}^{2} = \cancel \frac {1570}{15.70} \\ \\ ↝{r}^{2} = 100 \\ \\ ↝r = \sqrt{100} \\ \\↝ \dag {\boxed {\blue{ r = 10}}}$

Hence, the radius of base is 10 cm.