A right angled triangle of which the sides containing the right angle

1.	A right angled triangle of which the sides containing the right angle are 6.3 cm and 10 cm in length, is made to turn round on the longer side. Find the volume of the solid, thus generated. Also, find its curved surface.
Answer» We have, r = 6.3 cm, h = 10 cm ∴ l = \(\sqrt{r^2+h^2}\) cm = \(\sqrt{(6.3)^2+100}\) cm = \(\sqrt{139.69}\) cm = 11.82 cm Now, Volume = \(\frac{1}{3}\)×\(\frac{22}{7}\)×(6.3)²×10 cm³ = 415.8 cm³ Curved surface area = \(\frac{22}{7}\)×6.3×11.82 cm² = 234.03 cm²

A right angled triangle of which the sides containing the right angle are 6.3 cm and 10 cm in length, is made to turn round on the longer side. Find the volume of the solid, thus generated. Also, find its curved surface.

Answer»

We have,

r = 6.3 cm,

h = 10 cm

∴ l = \(\sqrt{r^2+h^2}\) cm

= \(\sqrt{(6.3)^2+100}\) cm

= \(\sqrt{139.69}\) cm

= 11.82 cm

Now,

Volume = \(\frac{1}{3}\)×\(\frac{22}{7}\)×(6.3)²×10 cm³

= 415.8 cm³

Curved surface area = \(\frac{22}{7}\)×6.3×11.82 cm²

= 234.03 cm²