The slant height of a conical mountian is 2.5 km and the area of its base is 1.54 km². The height of the mountain is:  Choose the correct choice from the following options:
A) 2.4 km
B) 2.6 km
C) 4.5 km
D) 5.4 km
E) None
Sol.   Let the radius of the base be r km. Then,   ∏r² = 1.54 ⇒ r² = [1.54 * 7 / 22= 
<gadget id="calculator">1.54 * 7 / 22</gadget>
<output>0.49</output>
0.49 ⇒ r= 0.7 km.   Now, l = 2.5 km, r = 0.7 km.   ∴ h = √(2.5)² = (0.7)² km = √6.25 - 0.49= 
<gadget id="calculator">6.25 - 0.49</gadget>
<output>5.76</output>
√5.76 km= 2.4 km   2.4 kmnswer 2.4 km
<result>A</result>
The slant height of a conical mountian is 2.5 km and the area of its base is 1.54 km². The height of the mountain is: