GEOMETRY: Chapter 9
9.5 Trigonometric Ratios PPT#2
Sine and Cosine Ratios
Image taken from: Geometry. McDougal Littell: Boston, 2007. P. 473.
Ex.1: Find sin A and sin B. Write each answer
as a fraction and as a decimal rounded to
four places.
Image taken from: Geometry. McDougal Littell: Boston, 2007. P. 474.
Ex.1: Find sin A and sin B. Write each answer
as a fraction and as a decimal rounded to
four places.
Answer: sin A = 8/17 ~ 0.4706
sin B= 15/17~0.8824
Image taken from: Geometry. McDougal Littell: Boston, 2007. P. 474.
Ex. 2: Find cos P and cos R. Write each answer
as a fraction and as a decimal rounded to four
places.
Images taken from: Geometry. McDougal Littell: Boston, 2007. P. 474.
Ex. 2: Find cos P and cos R. Write each answer
as a fraction and as a decimal rounded to four
places.
Answer: cos P =√5/3~0.7454; cos R=2/3~0.6667
Images taken from: Geometry. McDougal Littell: Boston, 2007. P. 474.
Ex. 3: A rope, staked 20 feet from the base of a
building, goes to the roof and forms an angle
of 58 degrees with the ground. To the
nearest tenth of a foot, how long is the rope?
Images taken from: Geometry. McDougal Littell: Boston, 2007. P. 475.
Ex. 3: A rope, staked 20 feet from the base of a
building, goes to the roof and forms an angle
of 58 degrees with the ground. To the
nearest tenth of a foot, how long is the rope?
Answer: 37.7 ft
Images taken from: Geometry. McDougal Littell: Boston, 2007. P. 475.
Angles—If you look up at an object, the angle
your line of sight makes with a horizontal
line is called the angle of elevation. If you
look down at an object, the angle your line
of sight makes with a horizontal line is
called the angle of depression.
Images taken from: Geometry. McDougal Littell: Boston, 2007. P. 475.
Ex. 4: A pilot is looking at an airport from her
plane. The angle of depression is 290. If the
plane is at an altitude of 10,000 feet,
approximately how far is it from the airport?
Answer: 20,627 ft
Ex. 5: A dog is looking at a squirrel at the top
of a tree. The distance between the two
animals is 55 feet and the angle of elevation
is 640. How high is the squirrel and how far
is the dog from the base of the tree?
Answer: 49.4ft high; 24.1 ft from the tree
9.5 p. 562-563 #3-36 all