Question

Lucas built a composite solid by joining 12 identical blocks, with dimensions 4 inches by 5 inches by 7 inches, into three

ows of four as shown.
7 in.
5 in
4 in
What is the total surface area of the composite solid?
O 521 square inches
1,042 square inches
1,072 square inches
O 1.992 square inches

Answer 1

Answer:The answer is (B.1,042)

Step-by-step explanation: i got it right

Answer 2

1042 square inches is the total surface area of composite solid.

Explanation:

It is clear from the image that the resulting composite solid is a cuboid.

whose sides are as follows:

Across the length there are 3 blocks along the side of 7 inches each.

Length =
`7 * 3 = 21\ inch`

Width = 5 inch

Across the height there are 4 blocks along the side of 4 inches each.

Height =
`4 * 4 = 16\ inch`

We know that total surface area of a cuboid is as follows:

`\text{Total Surface Area = } 2 (l* w+ w * h+ h * l)`

`\Rightarrow 2 (21 * 5 + 16 * 21 + 16 * 5 )\\\Rightarrow 2 (105 + 336+80)\\\Rightarrow 2 * 521\\\Rightarrow 1024`

Hence, total surface area = 1024 square inches