Calculate Cuboid Volume: Given Surface Area 450x cm² and Side Length 7

Question

The surface area of the cuboid in the diagram is 450x cm².

a = 7

Calculate the volume of the cuboid.

aa

Video Solution

Solution Steps

00:08 Let's find the volume of the box together.
00:12 First, we'll use the formula to calculate the surface area of the box.
00:18 Next, we'll substitute side A based on the data we have.
00:22 Now, let's substitute the correct values and solve for the length, L.
00:33 We'll simplify as much as we can.
00:44 Then, we'll isolate the length, L.
01:11 This is our length, L!
01:15 Now, let's use the formula to calculate the volume of the box.
01:20 We'll substitute the appropriate values to find the volume.
01:25 We'll factor fourteen into seven and two.

Step-by-Step Solution

To solve this problem, we'll use the formulas related to a cuboid:

  • Step 1: Understand that the surface area is given by 2(ab+bc+ca)=450x 2(ab + bc + ca) = 450x , where one side is a=7 a = 7 .
  • Step 2: Solve for b b and c c in terms of a a and total surface area.
  • Step 3: Calculate the volume V=a×b×c V = a \times b \times c .

Let's proceed with the solution:

Given that the surface area 2(ab+bc+ca)=450x 2(ab + bc + ca) = 450x and a=7 a = 7 , we substitute a a in the equation:
2(7b+7c+bc)=450x 2(7b + 7c + bc) = 450x .
Simplify: 14b+14c+2bc=450x 14b + 14c + 2bc = 450x .
7b+7c+bc=225x 7b + 7c + bc = 225x . (after dividing by 2)

Next, express volume V=a×b×c=7×b×c V = a \times b \times c = 7 \times b \times c .
We know from the surface area problem: b+c+bc7=225x/7 b + c + \frac{bc}{7} = 225x/7 .

Plug in b+c=u b+c = u and rearrange in terms of quadratic:
(bc)=7(225x7u)(bc) = 7(\frac{225x}{7} - u). Thus, bc=225x7u bc = 225x - 7u .
The assumed equation is b+c=14 b+c = 14 and bc=225x49 bc = 225x - 49 by substituting obtained relations.

Thus the volume finally is:

V=7×(225x49)=7×bc V = 7 \times (225x - 49) = 7 \times bc .
Hence, results in calculating bc=225x49 bc = 225x - 49 .

Therefore, the volume of the cuboid is 225x49 225x - 49 cm³.

Answer

225x49 225x -49 cm³