Give the demensions of a right triangle and a pararalogram with the same area

We are going to form a triangle of base 10 inches ans height 5 finches; also, the eight of our triangle will be the width of our rectangle (a rectangle is a parallelogram). First, we are going to use the area of a triangle formula: 
where 
is the area in square inches 
is the base of the triangle
is the height of the triangle
We know that  and , so lets replace those values in our formula:




Now that we have the area of our triangle, we are going to use the area of a rectangle formula: 
where
is the area in square inches 
is the width of the rectangle 
is the length of the rectangle 
Since the width of our rectangle is equal to the height of our triangle, . Also, we know for our problem that the area of our triangle and the area of our triangle must be equal, so . Lets replace those values in our formula to find the length of our rectangle:





We can conclude that the dimensions of our triangle are: base=10 inches and height= 5 inches, and the dimensions of our parallelogram are: width= 5 inches and length= 5 inches.

Iam thinking the answer is a.) knew