Part 5. Use the laws of sines. Please show work. Round to the nearest tenth.

 17) 41.0°      18) 60.8°       19) 36.0°        20) 19.7°

Step-by-step explanation:

Law of Cosines:    a² = b² + c² - 2bc · cos A

                              b² = a² + c² - 2ac · cos B

                              c² = a² + b² - 2ab · cos C

17) a = 29, b = 13, c = 21, C = ???

   c² = a² + b² - 2ab · cos C

21² = 29² + 13² - 2(29)(13) · cos C

441 = 841 + 169 - 754 cos C

441 = 1010 - 754 cos C

-569 = -754 cos C

41.0° = C

18) a = 29.3, b = 25.7, c = 16.8, B = ???

   b² = a² + c² - 2ac · cos B

25.7² = 29.3² + 16.8² - 2(29.3)(16.8) · cos B

660.49 = 858.49 + 282.24 - 984.48 cos B

660.49 = 1140.73 - 984.48 cos B

-480.24 = -984.48 cos B

60.8° = B

19) a = 12, b = 19, c = 11, A = ???

   a² = b² + c² - 2bc · cos A

12² = 19² + 11² - 2(19)(11) · cos A

144 = 361 + 121 - 418 cos A

144 = 482 - 418 cos A

-338 = -418 cos A

36.0° = A

20) a = 10, b = 9, c = 18, A = ???

   a² = b² + c² - 2bc · cos A

100² = 9² + 18² - 2(9)(18) · cos A

100 = 81 + 324 - 324 cos A

100 = 405 - 324 cos A

-305 = -324 cos A

19.7° = A

x + y = 90 5x – 10y = 90 90 – 10y = 5x 90 + 10y = 5x

step-by-step explanation:

last month maria hiked the 5-mile mountain trail a number of times and she hiked the 10-mile canal trail several times. let x represent the number of times she hiked the 5-mile trail, and let y represent the number of times she hiked the 10-mile trail. if she hiked a total of 90 miles, which equation can be used to find the number of times maria hiked each trail? x + y = 90 5x – 10y = 90 90 – 10y = 5x 90 + 10y = 5x

10.416 meters per second

step-by-step explanation:

distance=1 00 meters

time= 9.6 seconds in decimal form or 9 3/5 as a mixed number

average speed= 100/9.6

=10.416 meters per second or 10 52/125 as a mixed number.