What is a formula that can be used to find the area of one triangular section of the door how do you know the formula will work?

Step-by-step explanation:

Given

See attachment for complete question

Required

Determine the formula of one of the triangular sections

From the attachment, we have that:

The area of the triangle is:

How to know the formula works?

From the attachment, we can see that the rectangle is divided into two equal triangular sections.

The area of the rectangle is:

Because the rectangle is divided into two equal triangular sections.

This implies that, the area of one of the triangular sections is half the area of the rectangle.

So:

Substitute LB for the area of the rectangle

By comparison:

and are the same

62.5 paisa

step-by-step explanation:

4000*70 = 280000

280000-(2000*90) = 100000

4000-2400 = 1600

100000/1600 = 62.5

( give brainliest)