story problem

Question

A 20 x 30 inch white rect. Flag has a red isosceles triangle in the middle the triangle has a base of 18 inch and a height of 12 inches. What is the area of the white material in the flag

Answer 1

Here are our area formulas:

A_rec = lw

A_tri = bh/2

 

A_rec = 20 in * 30 in

A_rec = 600 in²

 

A_tri = 18 in * 12 in / 2

A_tri = 9 in * 12 in

A_tri = 108 in²

 

Now we subtract the red triangle from the white flag's area:

600 in² - 108 in² = 492 in²