Question

frustrm of a cone capacity to hold of 28.29liters of water its top and bottom radii are 28cm and 21cm find its height

Answer 1

Answer:

14.90 cm

Step-by-step explanation:

Volume of frustum = $\frac{\pi h}{3} (R^{2} + r^{2}  +Rr)$

so R=28 cm

r= 21 cm

Let the height be h

volume= 28.29 litres=28290 $cm^{2}$

so

28290= $\frac{\pi h}{3} (R^{2} + r^{2}  +Rr )$

28290= $\frac{3.14*h}{3} [28^{2} +21^{2} +(28*21) ]$

28290= $\frac{3.14*h}{3} [784 +441 +588 ]$

28290=$\frac{314*h}{300} [784 +441 +588 ]$

28290=$\frac{314*h}{300} [1813 ]$

28290*300=314*h*1813

thus

h=$\frac{28290*300}{314*1813}$

therefore,

h=14.90 cm