Step by step
The question
Question: find the area of the triangle with corners (0, 0), (6, 0), (2, 4).
1 Plot the points
We put the corners on the grid.
Corner A is (0, 0).
And so on.
We join them in order.
2 Find the base and height
base A B: the same y, so it goes across.
Its length is the bigger x minus the smaller: 6 minus 0 is 6.
The height goes straight down from C to the base line.
It goes from y = 4 to y = 0: 4 units.
3 Area
The area of a triangle is a half times base times height.
Careful!
Base times height is the whole rectangle around it.
The triangle is half of that.
Half of 6 times 4 is 12 square units.
4 Check
Let's check: the rectangle around the base and the height is 6 by 4: 24 squares.
The triangle takes half of it: 12.
So the answer is right!
Let's look back.
First: plot the points.
Then: find the base and height.
Then: area.
Last: check.