PSLE The perimeter of figure JKLMN is (10
s + 11) cm. The perimeter of square JKLM is 20 cm.
- Find the perimeter of triangle JMN in terms of s.
- The perimeter of figure JKLMN is 81 cm. What is the value of s? Give your answer in cm.
(a)
Length of the square
= 20 ÷ 4
= 5 cm
Total lengths of JK, KL and LM
= 3 x 5
= 15 cm
Perimeter of triangle JMN
= 10
s + 11 - 5 - 5
= (10
s + 1) cm
(b)
10
s + 11 = 81
10
s = 81 - 11
10
s = 70
s = 70 ÷ 10 = 7
Value of
s = 7 cm
Answer(s): (a) (10
s + 1) cm; (b) 7 cm