HPreCalc Chapter 6 Part 1 Test Flashcards
What is the alternative form of the law of cosines
CosA=b^2+c^2-a^2/2bc
Always use ______ decimals for problems with multiple steps
Unrounded
Why can’t you use the law of sines to find an obtuse angle
What should you do to avoid making this mistake
Law of sines has a domain that will make the angle either right or acute
Use law of cosines to find biggest angle first
When using Heron’s formula, look for __________ and __________
Perfect squares and repeated factors
If you have 45 in Heron’s formula, separate it into __ and ___
9 and 5 (take out a 3)
When finding a bearing in a triangle, start N or S. You can tell by seeing which one is closest to a ___ of that triangle
Side
When you are given three sides of a triangle, you use the Law of ___ to find the three angles of the triangle
Cosines
When you are given two angles and any side of a triangle, you use the law of ____ to solve the triangle
Sines
The law of cosines can be used to establish a formula for finding the area of a triangle;e called _____ ______ formula
Heron’s Area
When do you use law of cosines
SSS
SAS
When do you use law of sines
ASA, AAS, SSA
When is it not possible to use law of sines or law of cosines
AAA
What is ambiguous case
Explain
SSA
There can (possibly) be two triangles or even no triangles.
Find the height and decide
When you can make two triangles using ambiguous case, how do you find the second
Make the other angle its supplement (should be obtuse). Keep the two side lengths the same and solve
Oblique means
Not right or isosceles
What is the law of sines
A/sinA=B/sinB=C/sinC
Always check that the largest ____ matches up with the largest ____-
Angle, side
Obtuse oblique triangles can either have ___ or ___ triangles
How can you tell
One, no
The side opposite the largest angle must be the largest side
What is the area of an oblique triangle
When can this equation be used
Area=1/2bcsinA
SAS
An _____ triangle is a triangle that has no right angle
Oblique
For triangle ABC, the law of sines is a/sinA=_______=c/sinC
B/sinB
Two ____ and one ____ determine a unique triangle
Angles, side
The area of an oblique triangle is 1/2bcsinA=1/2absinC=_______
1/2acsinB
Given A=36 degrees and a=5
What is one possible combination for one solution, two solutions, and no solution
One solution- 5 is greater than or equal to b, b=5sin36
Two solutions- 5 is less than B and B is less than 5/sin36
No solution- b is greater than 5/sin36
What is the law of cosines
A^2=b^2+c^2-2bccosA
