PSLE The perimeter of figure PQRST is (9
m + 14) cm. The perimeter of square PQRS is 20 cm.
- Find the perimeter of triangle PST in terms of m.
- The perimeter of figure PQRST is 86 cm. What is the value of m? Give your answer in cm.
(a)
Length of the square
= 20 ÷ 4
= 5 cm
Total lengths of PQ, QR and RS
= 3 x 5
= 15 cm
Perimeter of triangle PST
= 9
m + 14 - 5 - 5
= (9
m + 4) cm
(b)
9
m + 14 = 86
9
m = 86 - 14
9
m = 72
m = 72 ÷ 9 = 8
Value of
m = 8 cm
Answer(s): (a) (9
m + 4) cm; (b) 8 cm