Question

a rectangle has side lengths of 2 and 39. below is the rectangle split into two small rectangles. (a) find the missing length, and then find the areas (in square units). (b) use the figure to find 2×39. 2 39 area = area = 9

Explanation:

Step1: Find the missing length

The large - rectangle has side lengths of 2 and 39. It is split into two smaller rectangles. One side of both smaller rectangles is 2. The length of the larger rectangle is 39, and one part of the length is 9. So the missing length is $39 - 9=30$.

Step2: Calculate the area of the top - rectangle

The area formula for a rectangle is $A = l\times w$. For the top - rectangle with length $l = 30$ and width $w = 2$, the area $A_1=30\times2 = 60$.

Step3: Calculate the area of the bottom - rectangle

For the bottom - rectangle with length $l = 9$ and width $w = 2$, the area $A_2=9\times2=18$.

Step4: Calculate $2\times39$

$2\times39=A_1 + A_2=60 + 18=78$.

Answer:

The missing length is 30. The area of the top - rectangle is 60 square units, the area of the bottom - rectangle is 18 square units, and $2\times39 = 78$.