Transcript opposite leg - Petal School District

Advanced Geometry
Trigonometry
Lesson 3
Trigonometry
Parts of a Right Triangle
adjacent
leg
hypotenuse – the side
of a right triangle
opposite the right angle
acute
angle
opposite leg
opposite
leg
acute
angle
adjacent leg
adjacent leg – the leg
of a right triangle that is
also a side of the given
acute angle
opposite leg – the leg
of a right triangle that is
not also a side of the
given acute angle
Sine Ratio
Abbreviated: sin
opposite leg
sin A 
hypotenuse
opposite leg
Cosine Ratio
Abbreviated: cos
adjacent leg
cos A 
hypotenuse
adjacent
leg
Tangent Ratio
Abbreviated: tan
opposite leg
tan A 
adjacent leg
adjacent
leg
opposite leg
Write the Ratio Problems
Example:
Use ∆ABC with right angle C to find sin A, cos A, tan A,
sin B, cos B, and tan B. Express each ratio as a fraction,
and as a decimal to the nearest hundredth.
AB = 17, BC = 15, and AC = 8
Find the Value Problems
Examples:
Use a calculator to find each value.
Round to the nearest ten-thousandth.
tan 56º
cos 89º
Missing Measure Problems
In problems where either
an angle OR side measure is missing,
set up a trigonometric ratio as shown below.
Name of the Angle Measure
Trig. Ratio
or variable
x
tan 47 =
10
= Ratio
Examples:
Find x. Round to the nearest tenth.
Examples:
Find x. Round to the nearest tenth.
Examples:
Find x. Round to the nearest tenth.
Example:
A fitness trainer sets the incline on a treadmill to 7º.
The walking surface is 5 feet long. Approximately
how many inches did the trainer raise the end of the
treadmill from the floor?
Example:
Find x and y. Round to the nearest tenth.