A cone of height 9 cm. with diameter of its base 18 cm. is carved out from a wooden soiled sphere of radius 9 cm. The percentage of the wood wasted is - 9 सेमी. ऊँचाई के शंकु के आधार का व्यास 18 सेमी. है, 9 सेमी. त्रिज्या वाले लकड़ी के ठोस गोले में से निकाला जाता है तो नष्ट हुई लकड़ी का प्रतिशत क्या है?

Volume of cone = (1/3)πr²h = (1/3)π × 9² × 9 = 243π cubic cm. Volume of sphere = (4/3)πr³ = (4/3)π × 9³ = 972π cubic cm. Wood wasted = (Volume of sphere - Volume of cone) / Volume of sphere × 100 = (972π - 243π) / 972π × 100 = 729/972 × 100 = 75%. The cone carved out uses only 25% of the sphere's volume, leaving 75% as waste.