Area Formulas

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6

A few weeks ago you learned that by reflecting a triangle, you can make a kite.

Slide 80

Kite

Now we have to determine the formula. What is the area of a triangle formula again?

Slide 81

Kite

Now we have to determine the formula. What is the area of a triangle formula again?

bh

2

Slide 82

Kite

Now we have to determine the formula. What is the area of a triangle formula again?

bh

2

Fill in the blank. A kite is made up of triangles.

Slide 83

Kite

Now we have to determine the formula. What is the area of a triangle formula again?

bh

2

Fill in the blank. A kite is made up of triangles.

So it seems we should multiply the formula by 2.

Slide 84

Kite

bh

2

*2 =

bh

Slide 85

Kite

Now we have a different problem. What is the base and height of a kite? The green line is called the symmetry line, and the red line is half the other diagonal.

bh

2

*2 =

bh

Slide 86

Kite

Let’s use kite vocabulary instead to create our formula.

Symmetry Line*Half the Other Diagonal

Slide 87

Practice!

Kite

2 ft

10 ft

Slide 88

Answers

20 ft2

Kite

2 ft

10 ft

Slide 89

Summary so far .

bh

Slide 90

Summary so far .

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Slide 91

Summary so far .

bh

Slide 92

Summary so far .

bh

bh

Slide 93

Summary so far .

bh

bh

2

Slide 94

Summary so far .

bh

bh

2

Slide 95

Summary so far .

bh

bh

2

Slide 96