Warm Up Problem of the Day Lesson Presentation Lesson Quizzes

Warm Up 1. True or false: If the height of a rectangle equals the base of a parallelogram and the base of the rectangle equals the height of the parallelogram, then the rectangle and the parallelogram have the same area. 2. Find the area of a rectangle with a length of 53 in. and a width of 47 in. True 2,491 in2

Which is a better deal, 3 discs for $5.00 or 4 discs for $7.00? Problem of the Day Which is a better deal, 3 discs for $5.00 or 4 discs for $7.00? 3/$5.00

Sunshine State Standards MA.6.A.3.4 Solve problems given a formula. Also MA.6.A.4.2, MA.6.G.4.3

You can divide any parallelogram into two congruent triangles You can divide any parallelogram into two congruent triangles. So the area of each triangle is half the area of the parallelogram.

Additional Example 1: Finding the Area of a Triangle Find the area of the triangle. 1 2 A = bh Write the formula. 1 2 Substitute 20 for b and 12 for h. A = (20 · 12) 1 2 A = (240) Multiply. A = 120 The area is 120 ft2.

Reading Math An altitude of a triangle is a perpendicular segment from one vertex to the line containing the opposite side. The length of the altitude is the height.

Find the area of the triangle. Check It Out: Example 1A Find the area of the triangle. 4 cm 11 cm A = bh = (11 • 4) = 22 cm 2 1 __

The diagram shows the floor plan for a triangular Check It Out: Example 1B The diagram shows the floor plan for a triangular dining area. What is the area of the floor? 6.2 m 34.8 m A = 1 2 bh = ( 34.8 • 6.2) = 107.88 m

Additional Example 2: Application The diagram shows the section of a forest being studied. What is the area of the section? 1 2 A = bh Write the formula. 1 2 Substitute 43.9 for b. Substitute 16 for h. A = (43.9 • 16) 1 2 A = (702.4) Multiply. A = 351.2 The area is 351.2 km2.

What is the height of the piece of wood?. Check It Out: Example 2A Mitch uses the piece of wood shown as part of a skateboard ramp. Its area is 0.8 m . 2 What is the height of the piece of wood?. A = bh; 0.8 = (2) 0.8 = h The height is 0.8 m. h 1 2 __ 2 m

Check It Out: Example 2B Mitch wants his skateboard ramp to be at least 750 cm tall. Should he use this piece of wood to build the ramp? Explain.?. Yes; the height is 0.8 m or 800 cm, which is greater than 750 cm.

Additional Example 3: Finding the Area of a Trapezoid Find the area of the trapezoid. 1 2 A = h(b1 + b2)‏ Use the formula. A = 1 2 · 4(14 + 12 )‏ Substitute 4 for h, 14 for b1, and 12 for b2. 1 2 A = 1 2 · 4(26 )‏ A = 53 Multiply. The area is 53 yd2.

Check It Out: Example 3A Lisa wants to cut a hole in the shape of a trapezoid out of a piece of wood. The figure shows her plans, and each square of the grid represents 1 ft . What is the area of the remaining wood after she cuts out the hole? 2

Check It Out: Example 3A continued 5 × 8 = 40; _ 1 (3 + 6)3 = 13.5; 2 40 - 13.5 = 26.5 2 The remaining area is 26.5 ft .

Check It Out: Example 3B The figure shows a vegetable garden that is planted with squash and carrots. To the nearest percent, how much of the vegetable garden is for squash?

Check It Out: Example 3B continued 1 _ 2 1 _ 2 _ 9 3 _ (8 + 6)3 = 21; (6)(3) = 9; = , or about 0.43 21 7 About 43% of the vegetable garden is for squash.

Lesson Quizzes Standard Lesson Quiz Lesson Quiz for Student Response Systems

Lesson Quiz Find the area of each triangle. 1. 3. 2. 39.9 cm2 84 mi2 113 in2 3 4 Find the area of each trapezoid. 4. 22.5 m2

Lesson Quiz for Student Response Systems 1. Find the area of the triangle. A. 48.3 cm2 B. 48.8 cm2 C. 52.3 cm2 D. 58.6 cm2

Lesson Quiz for Student Response Systems 2. Find the area of the triangle. A. 124 m2 B. 134 m2 C. 132 m2 D. 144 m2

Lesson Quiz for Student Response Systems 3. Find the area of the trapezoid. A. 37.2 m2 B. 35.8 m2 C. 33.4 m2 D. 32.6 m2