My Belt is Longest!
Take a thick paper sheet of length 14 cm and width 9 cm. You
can also use an old postcard.
* What is its area? What is its perimeter?
* Now cut strips of equal sizes out of it.
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Answers
Step-by-step explanation:
a) We know that,
Area of a rectangle = Length * Breadth
Area of a thick paper sheet = (Length * Breadth)
= (14*9) square cm = 126 square cm
Perimeter of a rectangular sheet
= 2(Length+ Breadth)
= 2(14 + 9) cm
= 2 * 23 cm = 46cm
(b) Let us cut strips of equal sizes out of the given paper sheet of length 14 cm and width 9 cm.
(c) Strips having width 1 cm:
There will be 9 strips of width 1 cm and length 14 cm. Let us join these strips end to end using tape to make a belt.
Its length
= (14+14+14+14+14+14+14+14+14)
= 9 * 14 cm = 126 cm
It’s perimeter = 2(126+1) cm = 2 127 cm = 254 cm
(d) Strips having length 1.5 cm:
There will be 6 strips of width 1.5 cm and length 14 cm. Let us join these strips end to end using tape to make a belt.
It’s length = (14+14+14+14+14+14) cm
= 6 * 14 cm = 84 cm
It’s perimeter = 2 (84 + 1.5) cm = 2* 85 – 5 cm = 171 cm
(e) Whose belt is the longest in the class?
Ans. (e) Strips having width 3 cm:
There will be 3 strips of width 3 cm and length 14 cm.
Let us join these strips end to end using tape to make a belt.
It’s length = (14+14+14) cm = 3 * 14 cm = 42 cm
It’s perimeter = 2(42+3) cm = 2 * 45 cm = 90 cm
Clearly, the belt with shortest width is the longest one. Thus, the belt having width 1 cm is the longest in the class. So, my belt is the longest.