Step-by-step explanation:
Since the triangles are right angled and are similar,
by Pythagoras theorem,
(10√3)^2 = (5√3)^2 + a^2
a = 15, a > 0
Topic: Pythagoras theorem
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V = 4/3πr^3V = 4/3 (π) (6.5)^3
V = 366.1666π (6 repeat)
answer is 366.16 π (3rd choice)