PSLE The perimeter of figure FGHJK is (10
r + 20) cm. The perimeter of square FGHJ is 12 cm.
- Find the perimeter of triangle FJK in terms of r.
- The perimeter of figure FGHJK is 60 cm. What is the value of r? Give your answer in cm.
(a)
Length of the square
= 12 ÷ 4
= 3 cm
Total lengths of FG, GH and HJ
= 3 x 3
= 9 cm
Perimeter of triangle FJK
= 10
r + 20 - 3 - 3
= (10
r + 14) cm
(b)
10
r + 20 = 60
10
r = 60 - 20
10
r = 40
r = 40 ÷ 10 = 4
Value of
r = 4 cm
Answer(s): (a) (10
r + 14) cm; (b) 4 cm