PSLEJohn had 2.8 m of ribbon. He used some of it to make the figure as shown.
- How much of the ribbon did Andy use to make the figure? Leave your answer in the simplest form in terms of r.
- If r = 20, how much of the ribbon was not used to make the figure? Leave your answer in meters.
(a)
Total length of ribbon used
= r + r + r + (3r - 3) + (r + 20)
= r + r + r + 3r + r - 3 + 20
= (7 r + 17) cm
(b)
1 m = 100 cm
2.8 m = 280 cm
Total length of ribbon used if r = 20
= 7 r + 17
= 7(20) + 17
= 140 + 17
= 157 cm
Total length of ribbon not used
= 280 - 157
= 123 cm
1 cm = 0.01 m
123 cm = 1.23 m
Answer(s): (a) (7r + 17) cm; (b) 1.23 m