MAT017
Applied Math II
Procedures
To Solve a Right Triangle
Tools and Rules
1.
Uppercase letters denote angles (C is always the right angle).
2.
Lowercase letters denote sides opposite angles (c is always the hypotenuse).
3.
The angles in a triangle add up to 180, therefore the 2 acute angles add up to 90.
4.
The Pythagorean Theorem:
c  a2  b2
5.
The Trig Functions:
opposite/hypotenuse
adjacent/hypotenuse
opposite/adjacent
Sin
Cos
Tan
To solve a right triangle, you use a combination of the tools and rules above, along with the
given/known data (sides and/or angles), to calculate the missing data until all three angles and all
three sides are known. Angle C will always be 90.
Example
B
Solve this triangle:
c
a
C
b
Angle A = ____________
Angle B = ____________
Angle C =
90
A
Side a = _______________
Side b = _______________
Side c = _______________
If Angle A or B is given/known, use the rule in # 3 above to calculate the missing angle.
If neither angle is given/known, use the Trig Functions from #5 above and the lengths of given sides
to calculate the angles.
If 2 sides are given/known, use the Pythagorean Theorem in #4 above to calculate the third side.
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