PSLEDavid had 2.8 m of string. He used some of it to make the figure as shown.
- How much of the string did Andy use to make the figure? Leave your answer in the simplest form in terms of x.
- If x = 20, how much of the string was not used to make the figure? Leave your answer in meters.
(a)
Total length of string used
= x + x + x + (3x - 8) + (x + 19)
= x + x + x + 3x + x - 8 + 19
= (7 x + 11) cm
(b)
1 m = 100 cm
2.8 m = 280 cm
Total length of string used if x = 20
= 7 x + 11
= 7(20) + 11
= 140 + 11
= 151 cm
Total length of string not used
= 280 - 151
= 129 cm
1 cm = 0.01 m
129 cm = 1.29 m
Answer(s): (a) (7x + 11) cm; (b) 1.29 m