Answer:
The first one is 360 degrees. The second one is 1080.
Step-by-step explanation:
The sum of the interior angles of a quadrilateral are always 360. If you subtract 90 from 360 to get 270. Multiply 270 by 4 to get 1080.
Answer:
how did you get those warning signs in your question
Step-by-step explanation:
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:
Length = 12 inches
Width = 14 inches
Step-by-step explanation:
Formula for perimeter of a rectangle is;
P = 2(L + W)
Where;
L is length
W is width
We are told that the length is 2 inches shorter than its width. Thus;
L = (W - 2)
Thus,perimeter is now;
P = 2(W - 2 + W)
P = 2(2W - 2)
P = 4W - 4
We are told that the perimeter is 52. Thus;
4W - 4 = 52
4W = 52 + 4
4W = 56
W = 56/4
W = 14 inches
From L = (W - 2) ;
L = 14 - 2
L = 12 inches
