PSLEWill had 3.4 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 r.
- If r = 10, how much of the string was not used to make the figure? Leave your answer in meters.
(a)
Total length of string used
= r + r + r + (3r - 9) + (r + 20)
= r + r + r + 3r + r - 9 + 20
= (7 r + 11) cm
(b)
1 m = 100 cm
3.4 m = 340 cm
Total length of string used if r = 10
= 7 r + 11
= 7(10) + 11
= 70 + 11
= 81 cm
Total length of string not used
= 340 - 81
= 259 cm
1 cm = 0.01 m
259 cm = 2.59 m
Answer(s): (a) (7r + 11) cm; (b) 2.59 m