Q. 104.7( 3 Votes )

ΔABC is an isosceles triangle with AB = AC = 13 cm and the length of altitude from A on BC is 5 cm. Then, BC = ?
A. 12 cm

B. 16 cm

C. 18 cm

D. 24 cm

Answer :


The given triangle is isosceles so the altitude from the one of the vertex is median for the side opposite to it.


AB = AC = 13 cm


h = 5 cm (altitude)


Δ ABX is a right angled triangle, right angled at X


(AB)2 = h2 + (BX)2 (BX = 1/2 BC)


169 = 25 + (BX) 2


BX = 12


BC = 24

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