240 is the answer you're looking for!
Explanation:
To find the area, spilt the trapezoid into 3 shapes.
2 triangles (at the ends) and 1 rectangle (the center).
Let's start with the rectangle, the formula for rectangle area is:

The length of the rectangle is 12, the width is 20. Add the numbers in:

Solve:

The area of the rectangle is 240. Now solve for the Triangles.
The formula for finding the area of triangles are is:

The length of the triangle is 12. To find the width subtract 20 from 30.
L = 12, W = 10. Add in the numbers.

Use order of operations to solve, start with parenthesis:

Rember to divide it by 2 because a triangle is half of a rectangle.

Since there are two identical triangles, you don't need to solve for the other
Now, add the areas together:

Then solve:


The correct answer is 240.