Answer:
see attached
Step-by-step explanation:
Each spot in the triangle is the sum of the two numbers immediately above. The middle number of row 2 will be 1+1 = 2. The two numbers in row 3 will be 1+2 = 3 and 2+1 = 3. It continues like this. The second number in each row is the row number. Each row is symmetrical about the center.
Find the area of the rectangle. You can find the area of a rectangle with the following formula:

w = width, and l = length.
Plug in your width and length:

The area of the rectangle is 200 square centimeters.
The area of a square is also given by width * length. Multiply the sides together:

The area of a square is 4x^2.
Because you're cutting away the square from the rectangle, you will subtract the area of the square from the area of the rectangle. The following equation will be your answer: