Step-by-step explanation:
(16 ×7×3)+(1/2×3×5×6)
=336+45
=381cubic inch
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:
The volume of given cone is 602.88 cube units
Step-by-step explanation:
<u>Formula:</u>
Volume of cone, V = πr²h
r - Radius of cone
h - height of cone
<u>To find the volume</u>
Here, r = 4 and h = 12
Volume V = πr²h
V = 3.14 *4²*12
V = 3.14*4*4*12
Volume V = 602.88
Therefore the volume of given cone is 602.88 cube units
Set up a proportion. 2/5 = x/40
to solve the equation first cross multiply.
x*5=40*2
x*5=80
now divide both sides by 5, 80 divided by 5 is equal to 16.
so the number of girls in the computer lab is 16.
