Helen draws a random circle, 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. Calculate the lower bound and upper bound for Helen's value of it.

Ascale drawing of a lake has a scale of 1 cm to 80 m. if the actual width of the lake is 1000 m what is the width of the lake on the scale drawing

Suppose you are choosing a 6-digit personal access code. this code is made up of 4 digits chosen from 1 to 9, followed by 2 letters chosen from a to z. any of these digits or letters can be repeated. find the total number of personal access codes that can be formed. 492,804 341,172 39,917,124 4,435,236

Gia opened two savings accounts at two different banks. one account earns an annual 3.4% simple interest, and the other earns half as much. if she deposited $500 in each account, how much total interest will she have earned in 5 years? a. $34.00 b. $25.50 c. $51.00 d. $510.00