Answer:B
Step-by-step explanation:
Because if you did not you would not have a exact answer.
The area formula of a circle is 
× π.
With that being said, we can solve both problems!
Starting with part A:
-The radius we know is 21cm. From there, we can substitute in our formula with the new value.
x π
From there, we can square our radius:
(21 x 21) x π
(441) x π
And finally, we can multiply by pi to get our answer.
(441) x π
1385.44236023
Which rounded to the nearest tenth is 1385.4. Therefore, the area of the porthole is 1385.4 centimetres.
The second part can be followed with the same process, hopefully you understand the concept enough to where you're comfortable solving problems like this on your own. Feel free to reach out if you have any further trouble!
<em>Hope this helped! :)</em>
5x + -4y = 13
Solving
-5x + -4y = 13
Solving for variable 'x'.
Move all terms containing x to the left, all other terms to the right.
Add '4y' to each side of the equation.
-5x + -4y + 4y = 13 + 4y
Combine like terms: -4y + 4y = 0
-5x + 0 = 13 + 4y
-5x = 13 + 4y
Divide each side by '-5'.
x = -2.6 + -0.8y
Simplifying
x = -2.6 + -0.8y
Simplifying
3x + -4y + -11 = 0
Reorder the terms:
-11 + 3x + -4y = 0
Solving
-11 + 3x + -4y = 0
Solving for variable 'x'.
Move all terms containing x to the left, all other terms to the right.
Add '11' to each side of the equation.
-11 + 3x + 11 + -4y = 0 + 11
Reorder the terms:
-11 + 11 + 3x + -4y = 0 + 11
Combine like terms: -11 + 11 = 0
0 + 3x + -4y = 0 + 11
3x + -4y = 0 + 11Combine like terms: 0 + 11 = 11
3x + -4y = 11
Add '4y' to each side of the equation.
3x + -4y + 4y = 11 + 4y
Combine like terms: -4y + 4y = 0
3x + 0 = 11 + 4y
3x = 11 + 4y
Divide each side by '3'.
x = 3.666666667 + 1.333333333y
Simplifying
x = 3.666666667 + 1.333333333y
Answer:
a:36 b:30
Step-by-step explanation:
A:180-56, since it is a straight line.
180-124-20= 36
B:180-120=60
60+3x+1x=180
60+4x=180
4x=120
x=30
