PSLE The perimeter of figure PQRST is (5
f + 11) cm. The perimeter of square PQRS is 8 cm.
- Find the perimeter of triangle PST in terms of f.
- The perimeter of figure PQRST is 56 cm. What is the value of f? Give your answer in cm.
(a)
Length of the square
= 8 ÷ 4
= 2 cm
Total lengths of PQ, QR and RS
= 3 x 2
= 6 cm
Perimeter of triangle PST
= 5
f + 11 - 2 - 2
= (5
f + 7) 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 + 7) cm; (b) 9 cm