Answer:
3.491
Step-by-step explanation:
move the decimal over 3 places.
Answer:
The area is:
, option b.
Step-by-step explanation:
Rectangular area:
The area of a rectangular space is given bt the multiplication of its measures.
Area of the roof:
Dimensions of 10x + 8 and 8x + 6. So
![A_{r} = (10x+8)(8x+6) = 80x^2 + 60x + 64x + 48 = 80x^2 + 124x + 48](https://tex.z-dn.net/?f=A_%7Br%7D%20%3D%20%2810x%2B8%29%288x%2B6%29%20%3D%2080x%5E2%20%2B%2060x%20%2B%2064x%20%2B%2048%20%3D%2080x%5E2%20%2B%20124x%20%2B%2048)
Area of the skylight:
Dimensions of x + 5 and 3x + 4. So
![A_{s} = (x+5)(3x+4) = 3x^2+4x+15x+20 = 3x^2 + 19x + 20](https://tex.z-dn.net/?f=A_%7Bs%7D%20%3D%20%28x%2B5%29%283x%2B4%29%20%3D%203x%5E2%2B4x%2B15x%2B20%20%3D%203x%5E2%20%2B%2019x%20%2B%2020)
What is the area of the remaining roof after the skylight is built?
Total subtracted by the skylight, which is a subtraction of a polynomial, in which we subtract the like terms. So
![A_{r} - A_{s} = 80x^2 + 124x + 48 - (3x^2 + 19x + 20) = 80x^2 - 3x^2 + 124x - 19x + 48 - 20 = 77x^2 + 105x + 28](https://tex.z-dn.net/?f=A_%7Br%7D%20-%20A_%7Bs%7D%20%3D%2080x%5E2%20%2B%20124x%20%2B%2048%20-%20%283x%5E2%20%2B%2019x%20%2B%2020%29%20%3D%2080x%5E2%20-%203x%5E2%20%2B%20124x%20-%2019x%20%2B%2048%20-%2020%20%3D%2077x%5E2%20%2B%20105x%20%2B%2028)
The area is:
, option b.
Answer:
11. 78
12. 4x² - 3x - 1
Step-by-step explanation:
11. Sum of n whole numbers = ½(n² + n)
Multiply
½*n² + ½*n
= n²/2 + n/2
To find the sum of the first 12 whole number, substitute 12 for n into the equation.
= 12²/2 + 12/2
= 144/2 + 12/2
= 72 + 6
= 78
12. Area of trapezoid = ½(a + b)*h
Where,
a = 5x - 4
b = 3x + 2
h = x + 1
Area = ½(5x - 4 + 3x + 2)*(x + 1)
Area = ½(8x - 2)*(x + 1)
Area = ½[8x(x + 1) -2(x + 1)]
= ½[8x² + 8x - 2x - 2]
Add like terms
= ½(8x² - 6x - 2)
= ½(8x²) - ½(6x) - ½(2)
= 4x² - 3x - 1
Answer:
Use the formula of areal*b*h