PSLE The perimeter of figure DEFGH is (5
f + 11) cm. The perimeter of square DEFG is 20 cm.
- Find the perimeter of triangle DGH in terms of f.
- The perimeter of figure DEFGH is 56 cm. What is the value of f? Give your answer in cm.
(a)
Length of the square
= 20 ÷ 4
= 5 cm
Total lengths of DE, EF and FG
= 3 x 5
= 15 cm
Perimeter of triangle DGH
= 5
f + 11 - 5 - 5
= (5
f + 1) cm
(b)
5
f + 11 = 56
5
f = 56 - 11
5
f = 45
f = 45 ÷ 5 = 9
Value of
f = 9 cm
Answer(s): (a) (5
f + 1) cm; (b) 9 cm