1. Merrill pg. 765, 10-18
feet meters feet meters meters ° 16. 1° °
18. x=63°, y=27°, z=63°

3. The Law of Sines
Section 14.1
MM4A6 & MM4A7

4. Essential Question
How do I solve problems using the Law of Sines?

5. Important information:
To find the area of a triangle using the sine function multiply one-half by the product of two sides and the sine of the included angle.
K = ½ (side)(side)(Sin of included angle)
Law of Sines: the ratio of the sine of an angle to its opposite side is the same for all angles in a triangle.

6. For ABC, the law of sines states the following:

7. Example 1
Find the area of ∆RST to the nearest tenth of a square unit.

8. Example 2
Find the area of ∆JKL to the nearest tenth of a square unit if m<K=59°, m<L=88°, side k=6.7in, and side l=8in.

9. Example 3
Find the area of ∆XYZ to the nearest tenth of a square unit.

10. Assignment Page 891, 10-23 ALL (make the angle in #22 B instead of C)
Using given information, ROUND all angles to the nearest WHOLE NUMBER before you work the problem!!

11. Do Now
Find the area of ∆ABC, m<A=51°, m<B=62°, side a=7 in., and side c=5.2

12. Pg. 891, 10-23 all 14.1 in.² 30 ft² 42.9 in.² 24.7 cm² 25.2 km²
ft² cm² km² ft² m² ft²

13. Example 4
Use the Law of Sines to find a & b.

14. Example 5
Solve ∆ PQR given the m<Q=115°, m<P=32°, and side p=5.6

15. Pg. 891, 24-29
8.6
8.3
13.8
9.6
15.8
17.1

16. Homework
Pg. 891, #’s all

17. Do Now
Find the area of ∆ABC, m<A=57°, m<B=68°, side a=5.6 in., and side c=7.1
Solve ∆ XYZ given the m<Y=119°, m<X=47°, and side x=6.5

18. Pg. 891, ODD
25. c = 8.3
27. a = 9.6
c = 17.1
31. A=101, b=3.5, a=7.5
33. C=83, b=12.3, c=13.8
35. A=80, b=10, c=3.5
37. A=97, a=20.8, c=15.5
39. B=101, a=12.3, c=13.6

19. Continued…
41. A=80, a=13.2, b= B=112, a=8.4, c=4.6

20. Pg. 891, even
24. b = b = a = C=85, a=17.3, c= B=100, b=28.8, c= C=95, a=5.9, b= C=80, b=7.4, c=11.4

21. Continued…
38. A=80, a=12.3, c= C=95, a=10.3, b= A=105, b=4.7, c=6.6

22. Info…
Quiz tomorrow over 14.1: finding the area of a triangle and solving triangles using the Law of Sines
Today, do page 985, 14.1, 1-14
Worksheet

23. Pg. 985, 14.1, 1-14 all 144.5 in² 16.6 m² 94 cm² 8.7 in² b=8.7 c=54.1
9. B=95, a=8.2, c= A=123, b=16.3, c= B=55, a=4.4, c= A=98, b=27.1, c= B=86, b=15.6, c= B=45, a=19.2, c=19.9

24. Workbook pg. 88, 1-12
25.5
24.8
16.7
29.7
5.6
28.9
C=38, b=4.4, c=3.1
A=35, c=21.7, a=12.7
9. C=45, a=25.8, c= B=44, a=5.5, b= C=82, a=15.5, c= A=75, a=82.9, c= ft.