Helen draws a random circle.
She then measures
its 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 value of rt using the formula
T= G
Calculate the upper bound for Helen's value of TC.
Give your answer correct to 3 decimal places.