Awindow has the shape of a rectangle with a semi circle at the top. find the approximate area of the window using the dimensions shown.
2ft by 4ft

First, let's find the area of the semi-circle.
Area of a circle = π*r²
Looking at the rectangle, the diameter for the circle is 2 ft. Since we need the radius though, divide the diameter by 2 to get the radius.
r = 1
A = π * 1²
A = π * 1
A = π

But since it's a semicircle, you need to divide that area by 2.
3.14/2 = 1.57

The area of the semi-circle is 1.57.

Area of a rectangle = lw
l = 2
w = 4
A = 2 * 4
A = 8

The area of the rectangle is 8.

Now add those together to get the area of the entire figure.

1.57 + 8 = 9.57

The figure is about 9.57 square feet.

No a triangle cannot be formed because when you add the two smallest number together (which would be 11) the have to be bigger than the number it is "against" ( which would be 12)