In the following question, two statements, (i) and (ii), are given. Choose the valid statement. The total surface area of a sphere is 154 cm2. Its radius will be 7 cm. For a cone; h2 = l2 + r2.

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

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CISCE(English Medium) ICSE Class 10

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Syllabus

In the following question, two statements, (i) and (ii), are given. Choose the valid statement. (i) The total surface area of a sphere is 154 cm2. Its radius will be 7 cm. (ii) For a cone;

Question

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

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

Options

Only (i)
Only (ii)
Both (i) and (ii)
Neither (i) nor (ii)

MCQ

Solution

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