Area Formulas - Weebly

Area Formulas Rectangle Rectangle What is the area formula? Rectangle

What is the area formula? bh Rectangle What is the area formula? bh

What other shape has 4 right angles? Rectangle What is the area formula? bh What other shape has 4 right angles?

Square! Rectangle What is the area formula? bh What other shape has 4 right angles?

Can we use the same area formula? Square! Rectangle What is the area formula? bh

What other shape has 4 right angles? Can we use the same area formula? Yes Square!

Practice! 17m 10m Rectangle Square

14cm Answers 17m 10m Rectangle

Square 170 m2 196 cm2 14cm So then what happens if we

cut a rectangle in half? What shape is made? Triangle So then what happens if we cut a rectangle in half? What shape is made?

Triangle So then what happens if we cut a rectangle in half? What shape is made? 2 Triangles Triangle So then what happens if we cut a rectangle in half?

What shape is made? 2 Triangles So then what happens to the formula? Triangle So then what happens if we cut a rectangle in half?

What shape is made? 2 Triangles bh So then what happens to the formula? Triangle So then what happens if we

cut a rectangle in half? What shape is made? 2 Triangles bh So then what happens to the formula? 2

Practice! Triangle 14 ft 5 ft Answers

Triangle 14 ft 5 ft 35 ft2 bh

Summary so far... bh Summary so far...

bh Summary so far... bh

Summary so far... bh bh Summary so far...

bh 2 Parallelogram Lets look at a parallelogram. Parallelogram Lets look at a

parallelogram. What happens if we slice off the slanted parts on the ends? Parallelogram Lets look at a parallelogram.

What happens if we slice off the slanted parts on the ends? Parallelogram Lets look at a parallelogram. What happens if we slice

off the slanted parts on the ends? Parallelogram Lets look at a parallelogram. What happens if we slice off the slanted parts on the

ends? Parallelogram Lets look at a parallelogram. What happens if we slice off the slanted parts on the ends?

Parallelogram Lets look at a parallelogram. What happens if we slice off the slanted parts on the ends?

Parallelogram Lets look at a parallelogram. What happens if we slice off the slanted parts on the ends? Parallelogram

Lets look at a parallelogram. What happens if we slice off the slanted parts on the ends? Parallelogram Lets look at a

parallelogram. What happens if we slice off the slanted parts on the ends? Parallelogram Lets look at a parallelogram.

What happens if we slice off the slanted parts on the ends? Parallelogram Lets look at a parallelogram. What happens if we slice

off the slanted parts on the ends? What will the area formula be now that it is a rectangle? Parallelogram Lets look at a parallelogram.

What happens if we slice off the slanted parts on the ends? What will the area formula be now that it is a rectangle? bh

Parallelogram Be careful though! The height has to be perpendicular from the base, just like the side of a rectangle!

bh Parallelogram Be careful though! The height has to be perpendicular from the base, just like the side of a rectangle!

bh Parallelogram Be careful though! The height has to be perpendicular from the base, just like the side of

a rectangle! bh Rhombus The rhombus is just a parallelogram with all equal sides! So it also

has bh for an area formula. bh Practice! 9 in

Parallelogram 3 in 2.7 cm Rhombus 4 cm

Answers 9 in Parallelogram 3 in

2.7 cm Rhombus 4 cm 27 in2 10.8 cm2

Lets try something new with the parallelogram. Lets try something new with the parallelogram. Earlier, you saw that you could use two trapezoids to make a parallelogram.

Lets try something new with the parallelogram. Earlier, you saw that you could use two trapezoids to make a parallelogram. Lets try to figure out the formula since we now

know the area formula for a parallelogram. Trapezoid Trapezoid Trapezoid

So we see that we are dividing the parallelogram in half. What will that do to the formula?

Trapezoid So we see that we are dividing the parallelogram in half. What will that do to the formula?

bh Trapezoid So we see that we are dividing the parallelogram

in half. What will that do to the formula? bh 2 Trapezoid

But now there is a problem. What is wrong with the base? bh 2 Trapezoid

So we need to account for the split base, by calling the top base, base 1, and the bottom base, base 2. By adding them together, we get the original base from the parallelogram.

The heights are the same, so no problem there. bh 2 Trapezoid

So we need to account for the split base, by calling the top base, base 1, and the bottom base, base 2. By adding them together, we get the original base from the parallelogram. The heights are the

same, so no problem there. base 2 base 1 base 1

base 2 (b1 + b2)h 2 Practice! 3m

Trapezoid 5m 11 m Answers 3m

Trapezoid 5m 11 m 35 m2

bh Summary so far... bh Summary so

far... bh Summary so far... bh

Summary so far... bh bh Summary so

far... bh 2 bh Summary so far...

bh 2 bh Summary so far... bh

2 bh Summary so far... bh 2

bh Summary so far... bh 2 bh

Summary so far... bh 2 bh

Summary so far... bh 2 bh Summary so

far... bh 2 bh Summary so far...

bh 2 bh Summary so far... bh

2 bh Summary so far... bh 2

(b1 + b2)h 2 bh Summary so far...

bh 2 (b1 + b2)h 2 bh

Summary so far... bh 2 (b1 + b2)h 2

bh Summary so far... bh 2 (b1 + b2)h 2

bh Summary so far... bh 2

(b1 + b2)h 2 bh Summary so far... bh

2 (b1 + b2)h 2 So there is just one more left!

So there is just one more left! Lets go back to the triangle. A few weeks ago you learned that by reflecting a triangle, you can make a kite.

Kite So there is just one more left! Lets go back to the triangle. A few weeks ago you learned that by

reflecting a triangle, you can make a kite. Kite Now we have to determine the formula. What is the area of a triangle

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

bh 2 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. 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. Kite bh *2 = bh 2 Kite

bh *2 = bh 2 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.

Kite Lets use kite vocabulary instead to create our formula. Symmetry Line*Half the Other Diagonal Practice!

Kite 2 ft 10 ft Answers Kite

2 ft 10 ft 20 ft2 bh Summary so

far... bh Summary so far... bh

Summary so far... bh Summary so far...

bh bh Summary so far... bh 2

bh Summary so far... bh 2 bh

Summary so far... bh 2 bh

Summary so far... bh 2 bh Summary so

far... bh 2 bh Summary so far...

bh 2 bh Summary so far... bh

2 bh Summary so far... bh 2