1. Area of Rectangles Return to table of contents

2. Area - The number of square units (units 2 ) it takes to cover the surface of a figure. ALWAYS label units 2 !!!

3. How many 1 ft 2 tiles does it take to cover the rectangle? Use the squares to find out! Look for a faster way than covering the whole figure. 12 ft 6 ft

4. A = length(width) A = lw A = side(side) A = s 2 The Area (A) of a rectangle is found by using the formula: The Area (A) of a square is found by using the formula:

5. 65What is the Area (A) of the figure? 15 ft 6 ft

6. 66Find the area of the figure below. 7

7. 67Dr. Dan wants to keep his kitten from running through his flower bed by putting up some fencing. The flower bed is 10 ft. by 6ft. Will Dr. Dan need to know the area or the perimeter of his flower bed to keep his kitty from trampling the flowers? AArea BPerimeter

8. 68Now solve the problem.... Dr. Dan wants to keep his kitten from running through his flower bed by putting up some fencing. The flower bed is 10 ft. by 6ft. How much fencing will he need?

9. Area of Parallelograms Return to table of contents

10. Area of a Parallelogram Let's use the same process as we did for the rectangle. How many 1 ft 2 tiles fit across the bottom of the parallelogram?

11. Area of a Parallelogram. Let's use the same process as we did for the rectangle. If we build the parallelogram with rows of 14 ft 2, what happens? How tall is the parallelogram? How can you tell? 14 ft

12. How does this help us find the area of the parallelogram? 14 ft How do you find the area of a parallelogram? 4 ft

13. A = base(height) A = bh The Area (A) of a parallelogram is found by using the formula: Note: The base & height always form a right angle!

14. Example. Find the area of the figure. 4 cm 2.2 cm 1.9 cm click to reveal

15. 4 Try These. Find the area of the figures. 8 75 click to reveal 11 m click to reveal 14 m 11 m 20 m

16. 69Find the area. 11 ft 10 ft 12 ft

17. 70Find the area. 17 in 10 in 12 in

18. 71Find the area. 7 m 13 m 7 m 11 m

19. 72Find the area.

20. Area of Triangles Return to table of contents

21. Area of a Triangle Let's use the same process as we did for the rectangle & parallelogram. How many 1 ft 2 tiles fit across the bottom of the triangle?

22. Area of a Triangle If we continue to build the triangle with rows of 10 ft 2, what happens? How tall is the triangle? How can you tell? 10 ft

23. How does this help us find the area of the triangle? Find the area of the rectangle, then divide by 2 20 ft 2 See that the rectangle we built is twice as large as the triangle. How do you find the area of a triangle? 10 ft 4 ft

24. Is this true for all triangles? Let's see! Calculating base(height) results in 2 triangles!

25. The Area (A) of a triangle is found by using the formula: Note: The base & height always form a right angle!

26. Example. Find the area of the figure. 4 cm 10 cm 6 cm click to reveal

27. Try These. Find the area of the figures. 13 ft 11 ft 9 ft12 ft 14 20 16 15 click to reveal

28. 73Find the area. 8 in 5 in 11 in 10 in

29. 74 Find the area 15 m 8 m 9 m 12 m

30. Area of Trapezoids Return to table of contents

31. Area of a Trapezoid ·Cut the trapezoid in half horizontally ·Rotate the top half so it lies next to the bottom half ·A parallelogram is created See the diagrams below Base 1 Base 2 Height Base 1 Base 2

32. The Area (A) of a trapezoid is found by using the formula: Note: The base & height always form a right angle!

33. Example. Find the area of the figure. 12 cm 10 cm11 cm 9 cm click to reveal

34. Try These. Find the area of the figures. 13 ft 11 ft 9 ft 11 ft 20 15 click to reveal 11 ft click to reveal 9117

35. 75Find the area of the trapezoid. 4 m 10 m 6.5 m

36. 76Find the area of the trapezoid. 22 cm 14 cm 8 cm

37. Area of Circles Return to table of contents

38. Area of a Circle The Area (A) of a Circle is found by solving the following formula:

39. 7 cm Find the area of the circle. A = π r 2 1. Substitute the radius into formula. A = π (7) 2 2. Use 3.14 as an approximation for π. A = 3.14(49) A = 153.86 cm 2 3. Don't forget to label the units as square units.

40. 77What is the Area (A) of a Circle with a radius (r) of 8 m? 8 m

41. 78What is the Area (A) of the circle?

42. 79What is the Area (A) of the circle?

43. 80A circular sprinkler sprays water with a radius of 11 ft. How much area can the sprinkler cover?

44. 81What is the area of a circle with a diameter of 24 yds?

45. 82What is the radius of a circle whose area is 254.34 mm 2 ?

46. 83A circular pool has an area of 153.86 ft 2. What is its diameter?