The Missing Sides/ Angles Of Non RightTriangle

Question 0

When u have SAS use

Answer 0

LAW OF COSINES to find the remaining side lengths

a^2 = b^2 + c^2 - 2bc • Cos(A)
b^2 = a^2 + c^2 - 2ac • Cos(B)
c^2 = a^2 + b^2 - 2ac • Cos(C)

Question 1

When u have ASA or AAA use

Answer 1

LAW OF SINES to find the remaining side lengths

a b c
—— = — = —–
Sin(A) Sin(B) Sin(C)

Question 2

review When given three sides of a RIGHT triangle, in order to find the angle measure use

Answer 2

90 as the reference angle and make the fraction accordingly

Ex:Sin(A) = 12 Cos(A) = 5 Tan(A) = 12
—- — —
13 13 5

Question 3

When given SSS of a NON RIGHT triangle use

Answer 3

(Reverse) LAW OF COSINES to find the missing angle

Cos(A) = b^2 + c^2 - a^2
——————–
2bc

Cos(B) = a^2 + c^2 - b^2
——————–
2ac

Cos(C) = a^2 + b^2 - c^2
——————-
2ab

• REMEMBER * solve for a fraction then use the Cos^-1 button in calc

Question 4

Ambiguous Case

Answer 4

Use (reverse) LAW OF SINES (SSA) to find the other angle
-This < measure is a positive acute < in quadrant 1
•Find all 3 <
-if reference < and obtuse Q2 < are less than 180 then there is a possible 2nd triangle