Question

In the following question, two statements, (i) and (ii), are given. Choose the valid statement.

1. The total surface area of a sphere is 154 cm². Its radius will be 7 cm.
2. For a cone; h² = l² + r².

विकल्प

• Only (i)

• Only (ii)

• Both (i) and (ii)

• Neither (i) nor (ii)

Answer 1

Neither (i) nor (ii)

Explanation:

• Statement (i) is invalid because a total surface area of 154 cm² corresponds to a radius of `sqrt((154 × 7)/(4 × 22))` = 3.5 cm, not 7 cm.
• Statement (ii) is also invalid because the correct relationship between the dimensions of a cone is given by Pythagoras' theorem as l² = h² + r², which means h² = l² − r²