PSLE The perimeter of figure ABCDE is (8
w + 15) cm. The perimeter of square ABCD is 20 cm.
- Find the perimeter of triangle ADE in terms of w.
- The perimeter of figure ABCDE is 71 cm. What is the value of w? Give your answer in cm.
(a)
Length of the square
= 20 ÷ 4
= 5 cm
Total lengths of AB, BC and CD
= 3 x 5
= 15 cm
Perimeter of triangle ADE
= 8
w + 15 - 5 - 5
= (8
w + 5) cm
(b)
8
w + 15 = 71
8
w = 71 - 15
8
w = 56
w = 56 ÷ 8 = 7
Value of
w = 7 cm
Answer(s): (a) (8
w + 5) cm; (b) 7 cm