Find the Slope of the Curve at the Indicated Point $\mathrm { T }$

Multiple Choice

Find the slope of the curve at the indicated point.
-A rectangular steel plate expands as it is heated. Find the rate of change of area with respect to temperature $\mathrm { T }$ when the width is $1.3 \mathrm {~cm}$ and the length is $2.2 \mathrm {~cm}$ if $\mathrm { dl } / \mathrm { dt } = 1.4 \times 10 ^ { - 5 } \mathrm {~cm} / { } ^ { \circ } \mathrm { C }$ and $\mathrm { dw } / \mathrm { dt } = 8.2 \times 10 ^ { - 6 } \mathrm {~cm} / { } ^ { \circ } \mathrm { C }$ .

A) $3.6 \times 10 ^ { - 5 } \mathrm {~cm} ^ { 2 } / { } ^ { \circ } \mathrm { C }$
B) $1.8 \times 10 ^ { - 5 } \mathrm {~cm} ^ { 2 } / { } ^ { \circ } \mathrm { C }$
C) $2.9 \times 10 ^ { - 5 } \mathrm {~cm} ^ { 2 } / \mathrm { C }$
D) $1.1 \times 10 ^ { - 5 } \mathrm {~cm} ^ { 2 } / { } ^ { \circ } \mathrm { C }$