What is the area of a triangle with vertices at (−2, 1) , (2, 1) , and (3, 4) ?

Steps:

1. Let the three points be as follows:

A(-2,1), B(2,1), C(3,4)

2. Use the distance formula for points to find the lengths AB, BC, and AC. You will need to use the formula 3 times.

3. Use Heron's formula

A = sqrt{s(s-AB)(s-BC)(A-AC)}

Note s = (AB + BC + AC)/2

GET STARTED NOW.

Check the picture below.

you can pretty much count the lengths off the grid.

recall that A = 1/2 bh.