I have a rectangle here with triangles inside.

some triangles are blank others are shaded.

-The area of the rectangle ABCD is 40in^2. What is the area of the unshaded region?

To find the area of the unshaded region, we need to first determine the area of the shaded region within the rectangle. Then we can subtract this area from the total area of the rectangle to get the area of the unshaded region.

To find the area of the rectangle, you need to know the lengths of its sides. Let's assume that the length of side AB is a units and the length of side AD is b units. Note that the opposite sides of a rectangle are equal in length.

Since the area of a rectangle is given by the formula A = length * width, we have:

Area of rectangle ABCD = a * b = 40 in^2 ----(1)

Now, let's move on to finding the area of the shaded region within the rectangle.

It seems that the shaded region consists of two triangles. To find the area of a triangle, we need to know the length of its base and its height (perpendicular distance from the base to the opposite vertex).

If you can provide more information about the dimensions of the triangles, such as the lengths of their bases and heights, we can proceed with calculating the area of the shaded region and then subtract it from the area of the rectangle to find the area of the unshaded region.