Geometry Practice Test 1

Question : 2 of 40

Marks: +1, -0

Suppose ΔABC be a right angled triangle, where ∠A = 90° and AD ⊥ BC. If ΔABC = 40.5 √3

cm^2

, ΔACD = 10

cm^2

and AC = 9 cm, then the length of BC is:

Solution:

Area of the right angle triangle
=

1/2

× 9 × AB =

40.5√3

AB =

2/9 (40.5√3)

{81}/9 √3

9√3

By Pythagoras theorem,

(BC)^2

(AC)^2 + (AB)^2

(9)^2+(9√3)^2

= 81 + 243

(BC)^2

= 324
BC = 18 cm

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