Answer:
The diameter of the circle is 9.
Step-by-step explanation:
Because circumference is equal to 
* d, we can backtrack and use this equation to find diameter. Let's say is equal to 3.14.
28.26 = 3.14d
Divide both sides by 3.14.
9 = d
The diameter of the circle is 9.
The sum of a trapezoid is 360 degrees
45+90+90+x=360
45+180+x=360
225+x=360
x=135
W=l-8
a=9
a=lw
9=(l-8)l
9=l²-8l
0=l²-8l-9
factor
0=(l-9)(l+1)
set to zero
l-9=0
l=9
l+1=0
l=-1, false length can't be negative
l=9
the length is 9 units long
S=4π<span>r<span>2 - this is the equation for the surface area of a sphere. We know that the radius (r) is 3.5 so here's how to solve this:
S = 4</span></span><span>π r2
S = 4</span><span>π (3.5)2
S = 4</span><span>π 12.25
S = 49</span><span>π
The surface area of a sphere with radius of 3.5 is 49</span><span>π.</span>
System of equations:
We'll need one equation for the amount of pizzas, and another for the total cost of the pizzas. In this case, x will represent small pizzas, and y will represent large pizzas.
3x + 4y = 100
x + y = 30
Solving the system of equations:
First, we need to solve for one variable in one equation.
x + y = 30
x = 30 - y
Then, we'll take our equation that is solved for x and plug it into the other equation from above.
3(30 - y) + 4y = 100
Next, we solve for y.
90 - 3y + 4y = 100
90 + y = 100
y = 10
Finally, we take our value for y and plug it back in to the very first equation and solve for x.
x = 30 - 10
x = 20
Answer:
The student has sold 10 large pizzas and 20 small pizzas.
Hope this helps!! :)
