Question

The dimensions of a closed rectangular box are measured as 90 centimeters, 50centimeters, and 90 centimeters, respectively, with the error in each measurement at most .2.2 centimeters. Use differentials to estimate the maximum error in calculating the surface area of the box.

Answer 1

184 cm²

Explanation:

Surface area of the rectangular box is expressed as S = 2(LW+LH+WH)

L is the length of the box = 90 cm

W is the width of the box = 50 cm

H is the height of the box= 90 cm

If there are error of at most 0.2 cm in each measurement, then the total surface area using differential estimate will be expressed as shown;

S = 2{(LdW+WdL) + (LdH+HdL) + (WdH+HdW)

Note that dL = dW = dH = 0.2 cm

Substituting the given values into the formula to estimate the maximum error in calculating the surface area of the box

S = 2{(90(0.2)+50(0.2)) + (90(0.2)+90(0.2)) + (50(0.2)+90(0.2))

S = 2{18+10+18+18+10+18}

S = 2(92)

S = 184 cm²

Hence, the maximum error in calculating the surface area of the box is 184cm²