Question

Que Height of a right circular cone is them. If its volume is a
1570 cm find the radius of its base. (π
= 3.14)​

Answer 1

Given:-

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

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.

Answer 2

Answer:-

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

Hence, the radius of base is 10 cm.