∆ ABC and ∆ DEF are similar triangles, and their areas are 81 cm2 and 144 cm, respectively. If EF = 20 cm, then what is the value of BC?
Show answer & explanation
Correct answer: C
Explanation
The correct answer is option 3 i.e. 15 cm.
Area of ∆ ABC / Area of ∆ DEF = (Corresponding side of ∆ ABC/ Corresponding side of ∆ DEF)2
⇒81/144 = ( BC/ EF)2
⇒9/12 = BC / 20
⇒ BC =( 20 × 9)/12 = 15 cm.
Hence, the length of BC is 15 cm.