Which expression can be used to model the phrase “the sum of three and a number”?
1 answer:
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9514 1404 393
Answer:
13 in by 51 in
Step-by-step explanation:
The area is the product of the dimensions, so is ...
663 = x(4x -1)
4x^2 -x -663 = 0 . . . . . . subtract 663 to put in standard form
Using the quadratic formula, we can find the solutions.
x = (-(-1) ±√((-1)^2 -4(4)(-663)))/(2(4))
x = (1 ± √10609)/8 = (1 ±103)/8
Only the positive solution is of any use in this problem, so ...
x = 104/8 = 13
4x-1 = 4(13)-1 = 51
The dimensions of the rectangle are 13 inches by 51 inches.
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I find it easiest to solve these using a graphing calculator.
I assume you meant "surface area" :)
Looking at the net, it looks like if you folded it back together it would form to become a triangular prism.
To calculate the surface area of a triangular prism, you would use the formula: A = bh + 2ls + lb, where b is the base of the triangular faces, h is the height of the prism, l is the length of the prism, and s is the side length of the prism.
I attached a picture to help you see what these labels are.
Looking at the diagram you've provided, we can assume that b = 7 cm, h = 4 cm, l = 8 cm, and s = 5 cm. Substitute these into the formula.
A = bh + 2ls + lb ==> A = (7)(4) + 2(8)(5) + (8)(7)
Multiply from left to right.
28 + 80 + 56
Add.
164
The surface area of this triangular prism is A) 164 cm^2.
