1. Area of triangles Unit 5

2. 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

3. Formula for area of a triangle.  Area equals one-half the base (b) times the height (h).  A = ½bh h b b h

4. 1. What is the area of the triangle? 4 in 8 in

5. 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

6. 2. What is the area of the triangle? 3 cm 9 cm

7.  In an obtuse triangle, you can extend a side to find the height. Obtuse Angle: Angle greater than 90˚

8. 3. What is the area of the triangle? 5 ft 12 ft

9. 4. What is the height of a triangle with an area of 40m 2 and a base of 10 m?

10. 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.

11. 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.

12. 7. The Area of a triangle is 30 yd 2 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.

13. 8. Mr. Butler drew these two triangles on the board:  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. 34 in 30 in 26 in 18 in 26 in Triangle A Triangle B