Area Area is the amount of surface space that a flat object has. Area is reported in the amount of square units.

When you measure the amount of carpet to cover the floor of a room, you measure it in square units. ? Would the area of your bedroom or the area of your house be greater? ? You’re right! The area of your house is greater than the area of your bedroom.

Lets find the area of this surface if each square is equal to one foot. Count the number of squares. 1 2 Area = 15 square feet 3 4 5 6 7 8 9 10 11 12 13 14 15

2 1 1 3 4 5 6 7 8 What is different about this shape? How will we find the area of this? 2 Why did I mark both of these as 1? 1 1 3 4 5 6 7 8 The area is equal to 8 square units.

Let’s find the area of this surface if each square is equal to one foot. Area = 15 square feet

Let’s find the area of this surface if each square is equal to one foot. The area is equal to 9.

1 2 3 4 5 6 7 8 9 The area is equal to 9 square units. Try this one! How could we find the area if we weren’t count the squares? Try this one! 1 2 3 4 5 6 7 8 9

How could we find the area if we weren’t count the squares? What is the formula for area? A=l*w 3 ft 3 ft

Time to Practice

Area of triangles

What’s the area of this rectangle? 10 cm 6 cm 60 cm2

What’s the area of the red triangle? 10 cm 6 cm 30 cm2 What would be a formula for area of a triangle?

Area of a triangle height length Area = ½ length x height

What’s the area? 4 cm 8 cm 16 cm2 ½ of 8 x 4 =

What’s the area? 8 cm 32 cm2 8 cm

What’s the area? 8 cm 12 cm2 3 cm

What’s the area? 2 cm 14 cm 14 cm2

What’s the area? 15cm 20cm 150 cm2

What’s the area? 20 cm 8 cm 80 cm2

What if the triangle doesn’t have a right angle?

Split it up! 4 cm 20 cm

Split it up! 20 cm (½ of 10 x 4) + ( ½ of 10 x 4) = 20 + 20 = 40

What’s the area? 10 cm 40 cm2 8 cm

Formulas to know: A = l*w A = 1/2 *b*h

TIME TO GET TRICKY!!

What is the area of each shape? 8 ft 6 ft B A C Subtract 16-8 to get = 8 and split that in half to get the length of each right triangle 4 ft Find the area of each triangle by multiplying .5*4*6 = 24 ft. for each triangle To get the square multiply 8*6 to get 48ft 16 ft

EVEN HARDER!

Point E is half way between A & B. What do you notice? Point E is half way between A & B. Here is some information: Side BD is 9 in. Side CD is 8 in. How can we find the area of all four shapes? A C E Split length in have to find length of each pink triangle which is 4 in. Find the area of the two right triangles. .5 *4*9 = 18 Find the area of the square 9*8 = 72 Subtract 72 from 18*2 to get Area is 36 in. Or Find the area of the square 9*8 = 72 in. And divide that by 2 to get 36in B D