Answer:
35 units
Step-by-step explanation:
Using Pythagoras Thereoem:
a² + b² = c²
21² + 28² = c²
c = √21² + 28² = √441 + 784 = √1,225 = 35 units
Step-by-step explanation:
First of all we need to know the formula for the circumference which is: 
We don't have the radius. What we only have is the area; therefore, we must use the area formula and extract the radius from it.
The formula for the area is:
Solve for r;
![r^2=\frac{A}{\pi}\\ r=\sqrt[]{\frac{A}{\pi} }](https://tex.z-dn.net/?f=r%5E2%3D%5Cfrac%7BA%7D%7B%5Cpi%7D%5C%5C%20r%3D%5Csqrt%5B%5D%7B%5Cfrac%7BA%7D%7B%5Cpi%7D%20%7D)
![r=\sqrt[]{\frac{50.24inch^2}{3.14} }](https://tex.z-dn.net/?f=r%3D%5Csqrt%5B%5D%7B%5Cfrac%7B50.24inch%5E2%7D%7B3.14%7D%20%7D)
![r=\sqrt[]{16inch^2}\\ r=4inch](https://tex.z-dn.net/?f=r%3D%5Csqrt%5B%5D%7B16inch%5E2%7D%5C%5C%20r%3D4inch)
Now that we've found the radius, we simply plug it into the circumference formula.

Answer:
They are not parallel
Step-by-step explanation:
original equation
10x + 3y = -3
subtract 10x
3y = -10x - 3
divide by 3
y = -10/3x - 1
original equation
5x - 4y = -3
subtract 5x
-4y = -5x-3
divide by -4
y = 5/4x + 3/4
the slopes are not equal to each other (5/4x and -10/3x) so they are not parallel