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When measuring the length a and the width b of a rectangle, it was found that 5.4< a< 5.5 and 3.6< b< 3.7 (in centimeters). Find the possible values of: the perimeter of the rectangle

1 Answer

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Answer:

The possible values of the perimeter of the rectangle is between 18 and

18.4 cm ⇒ [18 < perimeter of rectangle < 18.4] cm

Explanation:

* Lets explain how to solve the problem

- The perimeter of any quadrilateral is the sum of the length of its

four sides

- The rectangle is a quadrilateral with each two opposite sides are

equal in lengths, then its perimeter = 2l + 2w, where l, w are its

length and width

∵ The the length of the rectangle is a

∵ 5.4 < a < 5.5 cm

∵ The perimeter of the rectangle = 2a + 2b

- Lets multiply the inequality by 2

∴ 5.4 × 2 < a × 2 < 5.5 × 2

10.8 < 2a < 11 ⇒ (1)

∵ The width of the rectangle is b

∵ 3.6 < b < 3.7 cm

- Lets multiply the inequality by 2

∴ 3.6 × 2 < b × 2 < 3.7 × 2

7.2 < 2b < 7.4 ⇒ (2)

- Add inequalities (1) and (2)

∵ 10.8 < 2a < 11

+ 7.2 < 2b < 7.4

∴ 18 < 2a + 2b < 18.4

∵ 2a + 2b represents the perimeter of the rectangle

∴ The possible values of the perimeter of the rectangle is between

18 and 18.4 cm ⇒ [18 < perimeter of rectangle < 18.4] cm

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