Helen draws a random circle. She then measures it's diameter and circumference. She gets a circumference, (c), of 405 mm correct to 3 significant figures she gets a diameter, (d), of 130 mm correct to 2 significant figures. Helen wants to find the of value Pi using the formula pi= C/D. Calculate the lower bound and upper bound for Helen's value of Pi. Give your answer correct to 3 decimal place.
404.5 < c > 405.5
129.5 < d > 130.5
Largest possible number = UB/LB
Smallest possible number = LB/UB
405.5/129.5 = 3.13 (to 3 S.f)
404.5/130.5 = 3.09 (to 3 S.f)
3.09 < Pi > 3.13