3. You will find the apothem when there is no 300,600, 900 triangle.

4. Draw the radius Find the apothem for the following: 8cm There are 5 sections. So, take 360 0 and divide it by 5. 72 0 Next, take 72 0 and divide it by 2. 36 0 We don’t have a 36 0,54 0, 90 0 .

5. Since we have a right triangle, we can use trigonometry to find the apothem. Find the apothem for the following: 8cm 36 0

6. tan  = opposite / adjacent tan   = 4cm / apothem tan    / 1 = 4cm / apothem apothem  tan   = 4cm apothem = 4cm / tan 36 0 8cm 36 0 opposite 4cm a d j a c e n t apothem = 5.5cm

7. Now to find the area A = 1 / 2 aP 8cm 36 0 A = 1 / 2 ( 5.5 )(8+8+8+8+8) A = 110.11055cm 2

8. Theorem 10-8 The area of a triangle is one half the product of the lengths of the two sides and the sine of the included angle. A = 1 / 2 bc(sinA)

9. Let’s try it. Find the area for the following: 412ft. 386ft. 71 0 A = 75624.06 ft. 2 A = 1 / 2 (412)(386)(sin71 0 ) A = 1 / 2 bc(sinA)

11. Assignment Workbook Page 447 all