Lesson 7-1

Area of Parallelograms, Triangles, and Trapezoids

Area Formulas

• Parallelogram – base times height A = bh.

• Triangle – 1/2 base times height

• Trapezoid - 1/2 height times base one plus 1/2 height times base two.€

A =1

2bh

€

A =1

2h(b1 + b2)

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Find the area of the parallelogram.

7 cm

3 cm2 cm

Find the area of the triangle.

7 in4 in

22 in

Find the area of the trapezoid.

4.5 yd

5 yd3.4 yd 1 yd

A farmer plans to paint the triangular side of a large shed, shown below. Find the area to be painted. Assume that no part of the window needs to be painted. If a gallon of paint covers 350 square feet, how many gallons should the farmer buy?

25 ft

31 ft

3 ft

3 ft