The Area enclosed by the line y=4, the x axis, and the vertical lines x= 5, 10 is

I am trying to figure out how to work these problems out, if I could have someone to help me out that would be great?

Use what you already know for the following questions:

The Area enclosed by the line y=4, the x axis, and the vertical lines x= 5, and x= 10 is:

a) 5 b) 20 c) 4 d) 40

The area enclosed by (x-1)^2 + (y + 5)^2 = 49 is :
a)7 b) 49 c) 7pi d) 49 pi

The area enclosed by Y= (root 49 - x^2) is:
a) 7pi b) 7pi/2 c) 49pi d) 49pi/2

You have four lines forming a rectangle here. y = 0, y = 4, x = 5, x = 10.

Find the horizontal distance between the vertical lines.
delta x = 10 - 5 = 5.

Find the vertical distance between the horizontal lines.
delta y = 4 - 0 = 4.

Multiply them for the area of the rectangle.
Area = (5)*(4) = 20 square units.

Answer: b)

Second question
You have a circle with a radius of 7 units, since (x-1)^2 + (y+5)^2 = 7^2.
The area of a circle is pi (r)^2, so it will be 49 pi units squared.

Answer: d)

Third question
You have half a circle that is above the x-axis. Its radius is also 7 units. Since half a circle has half the area of a full circle, this area will be 49 pi/2 units squared.

Answer: d)