Area & Circumference

Warm-Up Find each product. 1.) ½ · 122.) 20 · ½ 3.) ½ · 16 Evaluate if a = 3, b = 4, and c = 6 4.) abc5.) ab ÷ 2 Solve for d using a = 3, b = 4, and c = 6 6.) cd = ab

Area of Parallelograms and Triangles The height of a parallelogram is the perpendicular distance from one base of a parallelogram to the other To find the area of a parallelogram use: Area = base · height Any side of a triangle can be considered the base of the triangle The height of a triangle is the length of the perpendicular segment from a vertex to the base opposite the vertex To find the area of a triangle use: Area = base · height ÷ 2

Examples Find the area of each parallelogram. 1.) 4 CM 2.) 6 CM 10 cm 14 cm

Examples Find the area of each triangle. 3.) 4.) 15 in 10 in 8 in 12 in

Example 5.) Determine the other length of a parallelogram that has a side length of 7 m and an area of 63 m². 6.) Determine the length of one side of square if the area is 64 in².

Homework Textbook pgs #1-22 A-Textbook pgs #2-14 Evens Only

Warm-Up Find the area of each parallelogram. 1.) b = 10, h = 12 2.) b = 7, h = 13 Find the area of each triangle. 3.) b = 10, h = 12 4.) b = 7, h = 13

Warm-Up A town plans to make a triangular park. The triangle has a base of 120 feet and a height of 115 feet. What will the area of the park be? ***Draw a picture first then solve.

Area of Trapezoids & Other Figures The two parallel sides of a trapezoid are the bases with lengths b 1 and b 2 The height h is the length of a perpendicular segment connecting the bases The formula for the area of a trapezoid follows the formula for area of a parallelogram( A = bh) Area of a Trapezoid:A = ½ · height(b 1 + b 2 )

Labeling the Trapezoid

Examples Find the area of each trapezoid. 1.) 2.) b 1 = 4 in b 2 = 8 in h = 5 in 3.) b 1 = 11 in b 2 = 16 in h = 8 in 10 m 12 m 8 m 20 m

Finding area of other figures To find the area of “other figures” or irregular figures, separate the figure into familiar figures(triangles, parallelogram, trapezoids) Then find the area of each piece and add the areas together

Examples 4.) 5.)

Homework Textbook pgs #1-13

Warm-Up Simplify. 1.) 1² 2.) 9² 3.) 11² 4.) 2 ∙ 3²

Circumference & Area of Circles Circumference is the distance around a circle To find circumference, use the formula: Circumference = π ∙ diameter or C = 2 ∙ π ∙ radius To find the area of a circle, use the formula: Area = π ∙ radius² *** π means pi(not “pie”) and it equals 3.14

Example(s): Find the circumference of each circle. 1.) d = 10m2.) r = 4in 3.)4.)

Example(s): Find the area of each circle. 1.) r = 4cm2.) d = 6ft 3.)4.)

Classwork Find the area and circumference of each circle. 1.) d = 3in 2.) r = 2m 3.) d = 7ft 4.) r = 6km 5.) d = 8mi

Homework Textbook pg. 422 #1-15 A-Textbook pg. 450 #1-18

Warm-up Solve each of the following. 1.) 4z = ) 33 = 3c 3.) 42 = 7f 4.) 3x + 5x = 48

Working Backwards? ***If you are given the circumference of a circle and you are to find the radius or diameter, think “backwards” ***work the problem backwards!