Triangle Area Sample Problems

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Here are some tips for Triangle Area, which aligns with Hawaii state standards:

Triangle Area

A triangle is a 3-sided shape.

The diagram shows the same triangle with different bases and heights.

Any side of the triangle can be the base.
The height of a triangle is always perpendicular to the base.

If you remember, the area formula for parallelograms is A = bh.
The area formula for triangles is half of that, A = ½ bh.

Why is the area formula for triangles ½ of the area formula for parallelograms?

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Take a triangle
(base and height labeled) Make a copy of the first triangle When you put the two triangles together,
they form a parallelogram.

Example:

area =

In the diagram, the height of the triangle is 4 cm.
The corresponding base is 6 cm.
The base is NOT 5 cm because the height is perpendicular to the side labeled 6 cm.
Now, put the values into the triangle area formula.

The answer is area = .

	→		→
Take a triangle (base and height labeled)		Make a copy of the first triangle		When you put the two triangles together, they form a parallelogram.