This is a Math Powerpoint presentation on how to find, the area of the different shapes.

1. How to Find … Created by Ryan Massey

4. Some of The “ 2-D ” Area Formula’s 3 6 5 10 2 Circles ½(bh)=A ½(5 x 10) =A ½ (50) = A 25 =A ½ (bh)= A Or Triangle bh = A 6 x 3 =A 18 =A bh = A (and another formula for the Square). Square / Rectangle ~~~~~~Example~~~~~~ Formula(s) Shape(s)

7. Practice Problems 5 7.5 A 3.95 B 19 14 ½ C

8. Problem A 5 7.5 Write out our formula.. (bh) = A Fill in the numbers that we know.. (5 x 7.5) = A

9. Problem A (cont.) 5 7.5 Multiply the numbers in the Parenthesis… (5 x 7.5) = A 37.5 = A

10. Problem B 3.95 Write out our formula.. (s) 2 = A Fill in the numbers that we know.. (3.95) 2 = A (3.95) 2 = A Square the number (3.95) 2 = 15.60 = A

11. Problem C 19 14 ½ Write out our formula.. (bh) = A Fill in the numbers that we know.. (19 x 14.5) = A

12. Problem C (cont.) Multiply the numbers in the Parenthesis… (19 x 14.5) = A 275.5 = A 19 14 ½

13. Our Area's are… 5 7.5 37.5 = A A 3.95 (3.95) 2 = 15.60 = A B 275.5 = A 19 14 ½ C

15. Triangles ( cont . ) The BLUE line is The Height of this Triangle. The RED Line is The Base of this Triangle . The GREEN Is the AREA Of this Triangle

16. Practice Problems with Triangles 24 12 10 5 19 4 A B C

17. (suggestions) !!!WAIT!!! Before we move on to see the answers, Go ahead and WORK-OUT the answers, then watch & see how's it done!!! Happy Calculating!

18. Problem A 24 12 A Write out our formula.. ½(bh) = A Fill in the numbers that we know.. ½(12 x 24) = A Click to See the Next set of Steps.

19. Problem A (cont.) 24 12 A Multiply the numbers in the Parenthesis… ½(12 x 24) = A ½ (288) = A Divide our area that we multiplied out by 2 or ½ . ½(288) = A ½(288) = 144

20. Problem B 10 5 B Write out our formula.. ½(bh) = A Fill in the numbers that we know.. ½( 5 x 10) = A Click to See the Next set of Steps.

21. Problem B (cont.) Multiply the numbers in the Parenthesis… ½(5 x 10) = A ½ (50) = A 10 5 B Divide our area that we multiplied out by 2 or ½ . ½(50) = A ½(50) = 25

22. Problem C 19 4 C Write out our formula.. ½(bh) = A Fill in the numbers that we know.. ½(4 x 19) = A

23. Problem C (cont.) 19 4 C Multiply the numbers in the Parenthesis… ½(4 x 19) = A ½ (76) = A Divide our area that we multiplied out by 2 or ½ . ½(76) = A ½(76) = 38

24. So… Our correct answers are.. A= 25 24 12 A A= 144 10 5 B 19 4 C A = 38

26. Quick Definitions Radius Diameter When the circle chows the Diameter, you still need to 1 st find the radius. And square the radius. ( Or your answer will be WRONG!) H I N T Is double of the radius .( Or ) The line that goes from one side of the circle to the other side, passing through the center of the circle. Diameter (in blue) The line that is ½ of the distance of the Diameter Radius ( or ) radii ( In red>>) Definition Name/ Hint

27. How do I find Area of a Circle? 2 Write out our formula.. Fill in the numbers that we know.. A= (3.14)(2) 2

28. Finding the Area of Circles (cont.) Multiply the Numbers in the Parenthesis Now, it is 6.28 to the 2 nd power. A= (3.14)(2) 2 A= 6.28 2 A= 6.28 2 A= 39.43 2

29. Practice Problems 5 8.5 30 Find the AREA Of the circles A-C a b c

30. Problem a 5 Write out our formula.. Fill in the numbers that we know.. A= (3.14)(5) 2

31. Problem a (cont.) Multiply the Numbers in the Parenthesis Now, it is 15.7 to the 2 nd power. A= (3.14)(5) 2 A= 15.7 2 A= 15.7 2 A= 246.49 5

32. Problem b 30 Write out our formula.. Fill in the numbers that we know.. A= (3.14)( 30 ) 2 We Need to now find The RADIUS of this Circle. 30/2 = 15 << 15 , is now The radii or radius for This problem.

33. Problem b (cont.) Multiply the Numbers in the Parenthesis Now, it is 47.1 to the 2 nd power. A= (3.14)(15) 2 A=47.1 2 A= 47.1 2 A= 2218.41 30

34. Problem c 8.5 Write out our formula.. Fill in the numbers that we know.. A= (3.14)(8.5) 2

35. Problem c (cont.) Multiply the Numbers in the Parenthesis Now, it is 26.69 to the 2 nd power. A= (3.14)(8.5) 2 A= 26.69 2 A= 26.69 2 A= 712.35 8.5

36. So… Our Area’s are… A= 246.49 5 A= 2218.41 30 A= 712.35 8.5