Question

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

Answer 1

Answer:

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

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

Step-by-step 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