Multiple choice

A solid cube of side 18.5 cm is heated such that its edges increase by 25%, then its surface area will increase by how much percent? एक 18.5 सेमी भुजा वाले ठोस घन को इस प्रकार गर्म किया गया कि इसकी भुजा में 25% की वृद्धि हुई, तो इसके पृष्ठीय क्षेत्रफल में कितने प्रतिशत की वृद्धि होगी?

  1. 25%

  2. 50%

  3. 62.5%

  4. 56.25%
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Surface area of cube = 6a² where a is edge length. When edge increases by 25%, new edge = 1.25a. New surface area = 6(1.25a)² = 6 × 1.5625a² = 9.375a². Percentage increase = (9.375 - 6)/6 × 100 = 56.25%.

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