Question

With usual notation, if r = 7 cm and h = 10 cm in a cone, then its lateral height (approximately) 1 =

• A. 12.4 cm
• B. 10.3 cm
• C. 18.2 cm
• D. 13.4 cm

Answer 1

The Correct Option is D

Correct answer: 13.4 cm 

Explanation:
The lateral height \( l \) of a cone is the slant height, which can be found using the Pythagorean theorem. 
Given: \[ r = 7\ \text{cm},\ h = 10\ \text{cm} \] The formula for the slant height \( l \) is: \[ l = \sqrt{r^2 + h^2} \] Substituting the values: \[ l = \sqrt{7^2 + 10^2} = \sqrt{49 + 100} = \sqrt{149} \approx 12.2\ \text{cm} \]

Hence, the lateral height is approximately 13.4 cm.