PSLE The perimeter of figure ABCDE is (7
w + 22) cm. The perimeter of square ABCD is 24 cm.
- Find the perimeter of triangle ADE in terms of w.
- The perimeter of figure ABCDE is 78 cm. What is the value of w? Give your answer in cm.
(a)
Length of the square
= 24 ÷ 4
= 6 cm
Total lengths of AB, BC and CD
= 3 x 6
= 18 cm
Perimeter of triangle ADE
= 7
w + 22 - 6 - 6
= (7
w + 10) cm
(b)
7
w + 22 = 78
7
w = 78 - 22
7
w = 56
w = 56 ÷ 7 = 8
Value of
w = 8 cm
Answer(s): (a) (7
w + 10) cm; (b) 8 cm