To find the expression for the volume of a triangular prism, we need to know the formula for the volume of a prism. The formula for the volume of any prism is given by:
Volume = Base Area * Height
In this case, the triangular prism has a right triangle as its base, with base length 4x and height 6, and the height of the prism is x 5.
Step 1: Find the area of the base triangle
The area of a triangle is given by the formula: Area = (1/2) * base * height. In this case, the base length is 4x and the height is 6. Therefore, the area of the base triangle is:
Base Area = (1/2) * (4x) * 6 = 12x
Step 2: Calculate the volume
Now that we have the base area and the height of the prism, we can calculate the volume using the formula:
Volume = Base Area * Height
Substituting the values we have:
Volume = 12x * (x 5)
Simplifying the expression:
Volume = 12x^2 + 60x
To find the volume when x = 3, we can substitute x = 3 into the expression:
Volume = 12(3)^2 + 60(3)
= 12(9) + 180
= 108 + 180
= 288
Therefore, when x = 3, the volume of the triangular prism is 288 units cubed.