6. Alan had 1.2 m of wire. He used some of it to make the figure shown below.
A pentagon is given, labelled from left to right and base: k cm, k cm, k cm, (k + 8)cm and (2 k - 5) cm.
(a) How much of the wire did Alan use to make the figure?
Leave your answer in the simplest form in terms of k.
(b) If k=15, how much of the wire was not used to make the figure?
k + k + k + (k + 8) + (2 k - 5) = (6 k + 3) cm
a) Alan used (6 k + 3) cm.
6 x 15 + 3 = 93
120 - 93 = 27 cm
It was 27 cm.
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As appeared in PSLE 2010 exam:
ReplyDeleteAlan had 1.2m of wire. He used some of it to make the figure shown below.
Figure is a 5-side diagram labelled from left to right and base: k cm, k cm, k cm, (k+8)cm and (2k-5) cm.
(a) How much of the wire did Alan use to make the figure?
Leave your answer in the simplest form in terms of k.
(b) If k=15, how much of the wire was not used to make the figure?
PS: "not" in part (b) of this question was highlighted in bold.