PSLEOscar 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 a.
- If a = 15, how much of the string was not used to make the figure? Leave your answer in meters.
(a)
Total length of string used
= a + a + a + (3a - 5) + (a + 15)
= a + a + a + 3a + a - 5 + 15
= (7 a + 10) cm
(b)
1 m = 100 cm
3.4 m = 340 cm
Total length of string used if a = 15
= 7 a + 10
= 7(15) + 10
= 105 + 10
= 115 cm
Total length of string not used
= 340 - 115
= 225 cm
1 cm = 0.01 m
225 cm = 2.25 m
Answer(s): (a) (7a + 10) cm; (b) 2.25 m