Answer:
Below in bold.
Step-by-step explanation:
First find the height by use Pythagoras theorem on the right triangle:
h = sqrt (5^2 - 4^2)
= sqrt 9
= 3.
Volume of the prism = area of the triangle * length
= 1/2 * 3 * 4 * 10
= 1/2 * 12 * 10
= 60 cm^3.
Total area = area of 2 triangles + area 0f 3 rectangles
= 2 * 1/2 * 3 * 4 + 3 * 10 + 4 * 10 + 5 * 10
= 12 + 30 + 40 + 50
= 132 cm^2.
Because the sofa usually sells for $800, we know that's 100% of the price.
100% = $800
Let's find 1%.
1% = $800/100
1% = $8
Next, multiply $8 by 75 to find the percent of the sofas price when it's $600.
75% = $600
We now know that $600 is 75% of the sofas original price.
100% - 75% = 25%
The percent of decrease I'm the sofas sale price is 25%.
Hope I got that right, the question was worded a little strangley so I wasn't quite sure what you were asking :)