PSLE The perimeter of figure ABCDE is (7
c + 11) cm. The perimeter of square ABCD is 12 cm.
- Find the perimeter of triangle ADE in terms of c.
- The perimeter of figure ABCDE is 53 cm. What is the value of c? Give your answer in cm.
(a)
Length of the square
= 12 ÷ 4
= 3 cm
Total lengths of AB, BC and CD
= 3 x 3
= 9 cm
Perimeter of triangle ADE
= 7
c + 11 - 3 - 3
= (7
c + 5) cm
(b)
7
c + 11 = 53
7
c = 53 - 11
7
c = 42
c = 42 ÷ 7 = 6
Value of
c = 6 cm
Answer(s): (a) (7
c + 5) cm; (b) 6 cm