Area of triangles

1 / 13

# Area of triangles - PowerPoint PPT Presentation

Area of triangles. Unit 5. Getting the idea. Area is a measure of the number of square units needed to cover a region. Square Unit is a square with a side length of 1 of any particular unit of measure. Square Inches = in 2 Square Centimeters = cm 2. Formula for area of a triangle.

I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.

## PowerPoint Slideshow about ' Area of triangles' - gyan

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript

### Area of triangles

Unit 5

Getting the idea
• Area is a measure of the number of square units needed to cover a region.
• Square Unit is a square with a side length of 1 of any particular unit of measure.
• Square Inches = in2
• Square Centimeters = cm2
Formula for area of a triangle.
• Area equals one-half the base (b) times the

height (h).

• A = ½bh

h

b

h

b

1. What is the area of the triangle?
• Step One: Determine the formula for the area of a triangle.
• A = ½ bh
• Step Two:Substitute the values for the baseand the height

into the formula.

• The base, b, measures 8 inches and the height, h, measures

4 inches.

• A = ½ (8)(4)
• Step Three: Multiply
• A = ½ (8)(4)
• A = ½ (32) = ● =
• A = *divide by 2*
• A = 16
• Step Four: Write the answer with correct unit of measure squared.
• Area = 16 in2

4 in

8 in

Right Triangle
• Remember that a right triangle has a hypotenuse and 2 sides called legs.
• The legs form a right angle.
• To find the area of a right triangle, use the legs as the base and height.

Hypotenuse

2. What is the area of the triangle?
• Step One: Determine the formula for the area of a triangle.
• A = ½ bh
• Step Two:Substitute the values for the base and the heightinto the formula.
• The base, b, measures 9 cm and the height, h, measures 3 cm.
• A = ½ (9)(3)
• Step Three: Multiply
• A = ½(9)(3)
• A = ½ (27) = ● =
• A = *divide by 2*
• A = 13.5
• Step Four: Write the answer with correct unit of measure

squared.

• Area = 13.5 cm2

3 cm

9 cm

Obtuse Angle: Angle greater than 90˚

3. What is the area of the triangle?
• Step One: Determine the formula for the area of a

triangle.

• A = ½ bh
• Step Two:Substitute the values for the base and the height

into the formula.

• The base, b, measures 12 feet and the height, h, measures 5 feet.
• A = ½ (12)(5)
• Step Three: Multiply
• A = ½(12)(5)
• A = ½ (60) = ● =
• A = *divide by 2*
• A = 30
• Step Four: Write the answer with correct unit of measure squared.
• Area = 30 ft2

5 ft

12 ft

4. What is the height of a triangle with an area of 40m2and a base of 10 m?
• Step One:Determine the formula for the area of a triangle.
• A = ½ bh
• Step Two:Substitute the values for the areaand the base into the formula.
• The Area , A, is 40 m2 and the base, b, measures 10 m.
• 40 = ½ (10)(h)
• Step Three: Solve the Equation
• 40 = ½ (10)(h) = ● (h) = (h) = 5h
• 40 = 5h *divide both sides of equal sign by 5 (isolate the variable)
• 8= h
• Step Four: Write the answer with correct unit of measure.
• height = 8 m

5. The Clarke family built a triangular deck at the back of their house. What Is the area of the triangular deck if the base is 9 yards and the height is 7 yards?

• Draw the triangular deck and label the base and the height.
• Write the formula for finding the area of a triangle.
• Substitute the base and height into the formula.
• Solve the formula to determine the area of the triangular deck.
6. A triangular pennant has a base that is 18 inches long and a height of 6 ½ inches. What is the area of the pennant?
• Draw the triangular pennant and label the base and the height.
• Write the formula for finding the area of a triangle.
• Substitute the base and height into the formula.
• Solve the formula to determine the area of the triangular pennant.
7. The Area of a triangle is 30 yd2 and its height is 6 yd. What is the length of the base?
• Write the formula for finding the area of a triangle.
• Substitute the Area and height into the formula.
• Solve the formula to determine the base of the triangle.
8. Mr. Butler drew these two triangles on the board:

34 in

34 in

• 1. What is the area of Triangle A?
• 2. What is the area of Triangle B?
• 3. Describe what you notice about the two triangles.

18 in

26 in

30 in

30 in

Triangle A

26 in

Triangle B