A cone of height 7 cm and radius 3 cm is carved from a cuboidal block of wood of dimensions 10 cm x 5 cm x 2 cm. The percentage wood wasted in the process is?
Answer & explanation
Correct answer: option 4
volume of block of word = 10 × 5 × 2 = 100 cm3
volume of cone = \(\frac{1}{3}\) \(\pi \) r2h
= \(\frac{1}{3}\) × \(\frac{22}{7}\) × 3 × 3 × 7
= 66 cm3
Wastage = 100 - 66 = 34
⇒ Waste percentage = \(\frac{34}{100}\) = 34%