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precalc laws
Question | Answer |
---|---|
situations for law of sines | AAS and ASA |
law of sines | a/sinA = b/sinB = c/sinC |
ambiguous case situations and steps | SSA, draw altitude and find h |
formula to find h | h = bsinA |
if angle A is acute | a=h, a<h, a>h and a>-b, a>h and a<b |
a=h | one right triangle |
a<h | no triangles |
a>h and a>-b | one triangle |
a>h and a<b | two triangles |
if angle A is obtuse | a<b, a>b |
a<b | no triangles |
a>b | one triangle |
situations for law of cosines | SSS and SAS |
law of cosines to find a missing side | a2 = b2 +c2 -2bcCosA |
law of cosines to find a missing angle | cosA = b2 + c2 - a2/ 2bc |
area of a triangle SAS | A = (1/2)absincC |
area of a triangle SSS | A = {s (s-a)(s-b)(s-c) |
semi- perimeter | s = a + b + c /2 |