PSLEOwen had 2.4 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 = 15, 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 + (2r - 10) + (r + 17)
= r + r + r + 2r + r - 10 + 17
= (6 r + 7) cm
(b)
1 m = 100 cm
2.4 m = 240 cm
Total length of string used if r = 15
= 6 r + 7
= 6(15) + 7
= 90 + 7
= 97 cm
Total length of string not used
= 240 - 97
= 143 cm
1 cm = 0.01 m
143 cm = 1.43 m
Answer(s): (a) (6r + 7) cm; (b) 1.43 m