PSLE The perimeter of figure ABCDE is (8
y + 15) cm. The perimeter of square ABCD is 24 cm.
- Find the perimeter of triangle ADE in terms of y.
- The perimeter of figure ABCDE is 71 cm. What is the value of y? 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
= 8
y + 15 - 6 - 6
= (8
y + 3) cm
(b)
8
y + 15 = 71
8
y = 71 - 15
8
y = 56
y = 56 ÷ 8 = 7
Value of
y = 7 cm
Answer(s): (a) (8
y + 3) cm; (b) 7 cm