review for test get out important paper # 5 and a calculator
TRANSCRIPT
Review for Test
Get out important paper # 5 and a calculator
• 5. A wireless company erects an 85-foot vertical cellular phone tower. Find the angle of elevation to the top of the tower from a point on the ground 110 feet from its base.
A. 63.2° B. 45.2° C. 37.7° D. 52.3°
A wall is leaning 6° from the vertical toward you. You are standing 40’ from the base of the wall, and the angle of elevation from your feet to the top of the wall is 22°. Find the height of the
wall to the nearest tenth of a foot.
Methods we currently have to solve triangles…
• Triangle Sum Theorem (angles add up to 180)
• Pythagorean Theorem• SOHCAHTOA• Law of Sines
But will they always work??????
Solve a triangle:a = 9, b = 3 and c = 11
We are going to have to have another method!!!!
• Law of Cosines:If you are looking for a side use
these:a2 = b2 + c2 – 2bc cos A b2 = a2 + c2 – 2ac cos Bc2 = a2 + b2 – 2ab cos C
– Law of Cosines:• If you are looking for an angle, use
these: 2 2 2
cos2
b c aA
bc
2 2 2
cos2
a c bB
ac
2 2 2
cos2
a b cC
ab
Solve a triangle:a = 9, b = 3 and c = 11
Solve this triangle:A = 108, b = 10 and c = 6.5
Mount St. Helens' lava dome in August 1981, as viewed from a photo station, 1/2 mile away. In this view the dome is 535 feet high and nearly 1/4 mile wide.
Mount St. Helens' lava dome in August 1981, as viewed from a photo station, 1/2 mile away. In this view the dome is 535 feet high and nearly 1/4 mile wide, making it tallerthan a 44-story building (or, nearly the height of the Washington Monument) and wider than the length of four football fields. Compare with image taken August 12, 1985 from the same location with the same camera.
AC=
BC=
Use SOHCAHTOA to find the the measure of Angle A.
A volcanologist at A made EDM measurements of a lava dome as
shown. Use the Law of Cosines to find BD. Then find the height of the dome.
BD = _______________Height of dome = _______________
