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How much paint do we need to paint all the rooms in our house?

kitchen. TV room. bedroom. Area. How much paint do we need to paint all the rooms in our house?. Square Area = s 2 (s = side length) Rectangle Area = lw (l = length and w = width) Triangle Area = ½bh (b = base and h = height). You can justify the area formula for triangles as follows:.

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How much paint do we need to paint all the rooms in our house?

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  1. kitchen TV room bedroom Area How much paint do we need to paint all the rooms in our house?

  2. Square Area = s2 (s = side length) Rectangle Area = lw (l = length and w = width) Triangle Area = ½bh (b = base and h = height)

  3. You can justify the area formula for triangles as follows: The area of a triangle is half the area of a parallelogram with the same base and height. Area of a Parallelogram = bh Area of a Triangle = ½bh

  4. Be careful when identifying the height of a triangle! The height is NEVER a side of a triangle unless the triangle is RIGHT. h h h

  5. 8 cm 8 cm 8 cm 8 cm Ex 1: Find the area of.. a. A square whose sides have length 8 cm. A = s2 A = 82 A = 64 cm2

  6. b. A rectangle whose length is 5 m and width is 11 m. 5 m A = lw A = (5)(11) A = 55 m2 11 m 11 m 5 m

  7. 5 in 4 in 3 in c. A triangle whose side lengths are 3 in, 4 in, and 5 in. A = ½ (4)(3) A = ½ (12) A = 6 in2

  8. Ex 2: Find the indicated side length. a. A square with area 256 in2. 16 in A = s2 256 = s2 16 = s 16 in 16 in 16 in

  9. b. A rectangle with area 345 ft and length 15 ft. 15 ft A = lw 345 = 15w 23 ft = w 23 ft 23 ft 15 ft

  10. c. A triangle with area 12 mm and a base length of 6 mm. A = ½ bh 12 = ½ (6)h 12 = 3h 4 mm = h 4 mm 6 mm

  11. Parallelogram Area = bh (b = base and h = height) Trapezoid Area = ½ h (b1 + b2) Rhombus Area = ½d1d2 (d = diagonal)

  12. The area of a parallelogram is the area of a rectangle with the same base and height. You can justify the area formula for parallelograms as follows: h Area of Parallelogram = bh

  13. B C 9 16 E 12 A 12 D F Ex 3: Find the area of parallelogram ABCD Method 1 Use AB as the base and BE as the height.

  14. Ex 3: Find the area of parallelogram ABCD C B 9 16 E 12 A 12 D F Method 2 Use AD as the base and CF as the height. You get the same answer.

  15. Ex 4: Find the area of trapezoid WXYZ. Y(2, 5) Z(5, 5) X(1, 1) W(8, 1) Count the blocks for height, base 1, and base 2.

  16. Ex 5:The area of a trapezoid is 135 cm2, height is 9, and one bases is 11. Find the other base.

  17. 9 12 12 9 Ex 6: Find the area of the rhombus.

  18. Ex 7: The area of a rhombus is 40 in2 and one of the diagonals is 8 in. Find the other diagonal.

  19. Circle Area = Ex 8: Find the area if the radius . Leave your answer in terms of pi unless stated otherwise.

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