Multiple choice

The sum of all three sides of two similar triangles PQR and ABC are 46.8cm and 78cm respectively. If the length of side PQ is 11.7, then find the length of side AB?

  1. 24cm

  2. 23.4cm

  3. 19.5cm

  4. 20cm

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

For similar triangles, ratio of perimeters equals ratio of corresponding sides. Perimeter PQR/Perimeter ABC = 46.8/78 = 0.6. So PQ/AB = 0.6, giving AB = 11.7/0.6 = 19.5cm.