Question

Malia is placing a barrier around the edge of a circular path with a diameter of 13 m. The barriers are in lengths of 2.5 m. What is the best approximation of how many pieces of barrier Malia will need? Use 3.14 to approximate for π .

A. 5
B. 17
C. 33
D. 53

Answer 1

Hence, option B is correct (17)

Explanation:

Malia is placing a barrier around the edge of a circular path with a diameter of 13 m.

The barriers are in lengths of 2.5 m.

Let 'b' denotes the total number of barriers used.

Now the barrier will cover the circumference of the circle.

`2\pi r=2.5* b`

Where r denotes the radius of the circle.

The diameter of the circle is given as 13 m.

This means radius of circle=(13/2) m.

`2* 3.14* ((13)/(2))=2.5* b`

⇒ b=16.328

As the barriers will be used as a whole.

Hence, the Number of pieces of barrier Malia will need is 17.

Hence, option B is correct.

Answer 2

let b be the number of barriers
so the circumference of the edge is C= 2 x r x π, the total of circumference is equal to the number of barriers, so C=2.5b, and then 2.5 b = 2 x r x π,
so b = 2 x r x π/2.5= 32.65, the approximative value is 33,
the answer is C. 33