Question

a formula for determining the rate of increase in size for a geometric area in two - dimensional space when the rate is constant can be calculated by subtracting the original area from the new area and dividing by elapsed time, such that: $\frac{a_1 - a_0}{t}$ or $(a_1 - a_0)div t$. for a rectangular geometric area with $a = l\times w$, the formula could be rewritten as follows: $\frac{(l_1w_1)-(l_0w_0)}{t}$. solve for a geometric rectangular area in rate of expansion in square units per second with a length of 7 units and width of 14 units at start, or $l_0$ and $w_0$, and a length of 13 units and a width of 19 units after expanding. or $l_1$ and $w_1$, over 20 seconds. (you do not need to include the units. only enter the number value for an answer. round to the nearest hundredth if necessary.)

Explanation:

Step1: Calculate initial area

$A_0 = L_0\times W_0=7\times14 = 98$

Step2: Calculate new area

$A_1 = L_1\times W_1=13\times19 = 247$

Step3: Calculate rate of expansion

$\text{Rate}=\frac{(L_1W_1)-(L_0W_0)}{t}=\frac{247 - 98}{20}=\frac{149}{20}=7.45$

Answer:

$7.45$