Answer:
Find half the area of the rectangle
Step-by-step explanation:
Given
See attachment for the Serek's steps
Required
Which can be used to determine the area of the original triangle
To do this, we simply analyze each step.
At step 2, where he joined two congruent triangles to form a parallelogram.
Half the area of the parallelogram will give the area of the original triangle (since both triangles are equal)
At step 3, where he decomposed the parallelogram to a trapezoid and a right triangle.
Half the sum of the areas of the resulting shapes (trapezoid and right triangle) will equal to the area of the original triangle but half the area of each shape will not amount to the area of the original triangle
At step 4, where the right triangle and the trapezoid are merged to form a rectangle.
The area of the rectangle will equal to the area of the parallelogram in step (2).
So, half the area of the rectangle will equal to the area of the triangle.
Hence, (b) is correct