Question

Using a tape measure Becky Jo found that the circumference of the great redwood was 900cm. She estimated that its diameter was 300cm. Was her estimate a little too large or a little too small? Why?

Answer 1

The length of the circle - the product of the diameter and the number Pi
l = dπ
l = 900cm
π ≈ 3,1415 przyjmiemy wartość 3
900cm = d* 3   [:3
d = 300cm  
Becky rounded value of Pi , hence the difference in result

More accurate calculation

l = d*π
900cm = d*3,1415
d = 900cm : 3,1415 = 286,49cm

Becky overestimated the outcome