Surface Areas and Volumes
NCERT Exemplar Ch 11
CBSE_NCERT_EXEMPLAR_CH11
Grade 10
Question:
If the slant height of a cone is $13\text{ cm}$ and its base radius is $5\text{ cm}$, then its height is:
$12\text{ cm}$
$8\text{ cm}$
$18\text{ cm}$
$10\text{ cm}$
Step-by-Step Solution
Key Concept: Height $h = \sqrt{l^2 - r^2} = \sqrt{13^2 - 5^2} = 12\text{ cm}$.
Stepwise Solution:
$h = \sqrt{169 - 25} = \sqrt{144} = 12\text{ cm}$. [1.0 Mark]
Marking Scheme:
• Applying Pythagoras to find height $= 12\text{ cm}$: 1.0 Mark
Correct Answer: $12\text{ cm}$
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