Presentation on theme: "Area Area problems involve finding the surface area for a two-dimensional figure."— Presentation transcript:
1AreaArea problems involve finding the surface area for a two-dimensional figure.
2AreaArea problems involve finding the surface area for two-dimensional figures.What is surface area: it is the amount of space on the front of a two-dimensional figure. Suppose you were painting a wall, you would need to know the surface area so you would know how much paint to buy.
3Two-DimensionalTwo dimensional means a shape has only two measurements: either length and width, base and height, etc.Example: the Area formula for a rectangle is:A = lw or Area = length times widthYou used two dimensions to calculate with.What dimension you don’t calculate is depth.
4What Shapes? We will be calculating area for: Squares Rectangles RhombusParallelogramTrapezoidTriangleCircle
5Square The area formula for a square is: s² That is side squared. Remember all sides of a square are equalExample: the area for a square with sides of 5 inches: A = 5² or 25 inches²
6Rectangle The area formula for a rectangle is: A = lw That means A = length times widthExample: a rectangle with a length of 20 feet and a width of 10 feet: A = 20 • 10 or 200 ft.²
7Rhombus & Parallelogram They have the same area formula:A = bh or Area = base times the heightThe base and height will be marked so you can calculate very easily.Example: a parallelogram with a base of 10 cm and a height of 4 cm = A = 4 • 10 = 40cm²
8TrapezoidThe area formula for a trapezoid is the most difficult: ½h(b₁ + b₂)That is half (.5) the height times the sum of the top base and the bottom base.
9Circle Area formula for a circle: A = πr² Remember: pi = 3.14 (π) r = radius²Example: circle with a radius of 3 inches:3.14 • 3² = 3.14 • 9 or in.²
10Triangle Area formula for a triangle: A = ½bh or Area = one half (.5) the base times the heightExample: a triangle with a base of 12 mm and a height of 10 mm = .5 • 12 • 10 = 60mm²
11Area Is it a useful problem especially if you are: In the field of constructionIn the field of roofingIn the field of plastering or paintingIn the field of sewing, designing