Question

The height and the slant height of a cone are 21 cm and 28cm respectively find the radius and the volume of cone

Answer 1

☆☆ranshsangwan☆☆

slant height)² = (radius )² + ( height)²
⇒radius² = (28)² - (21)²
               = (28 +21) (28- 21)
               = 49 × 7
●●radius● = 7√7 cm
now, volume = ( π r² h)/3
                     =((22/7)× 343× 21)/3
                     = 7546 cm³
∴ volume = 7546 cm³

Answer 2

Hey friend, Harish here.

Here is your answer:

Given that,

Height = 21

Slant height = 28cm

We know that,

$radius = \sqrt{slant\ height^{2} - height^{2}}$

$= \sqrt{28^{2} - 21^{2}}$

$= \sqrt{784 - 441}$

$= \sqrt{343}$

$= 7 \sqrt{7} cm$

Therefore radius is 7√7 cm .

$Volume = \frac{1}{3} \times \pi \times r^{2} \times h$

$= \frac{1}{3} \times \frac{22}{7} \times 343 \times 21$

$=7546\ cm^{3}$

Therefore, Volume is 7546 cm³.
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Hope my answer is helpful to you.