Trigonometry & Applications Flashcards
7 cards from real Geometry practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Trigonometry & Applications flashcards as text
Using the Law of Sines, if a = 8, angle A = 30°, and angle B = 45°, which sets up side b?
Answer: b = 8 sin 45° / sin 30°
By the Law of Sines a/sin A = b/sin B, so b = 8 sin 45°/sin 30°.
The Law of Cosines c² = a² + b² − 2ab cos C reduces to the Pythagorean theorem when C equals what?
Answer: 90°
At C = 90°, cos C = 0, leaving c² = a² + b².
In triangle with sides a = 5, b = 7 and included angle C = 60°, what is c²?
Answer: 39
c² = 25 + 49 − 2(5)(7)(0.5) = 74 − 35 = 39.
What is the area of a triangle with sides 6 and 10 and an included angle of 30°?
Answer: 15
Area = ½·6·10·sin 30° = ½·60·0.5 = 15.
When is the Law of Cosines preferred over the Law of Sines?
Answer: Given SAS or SSS
The Law of Cosines works directly with SAS or SSS configurations.
In triangle ABC, angle A = 40°, angle B = 60°. What is angle C?
Answer: 80°
Angles sum to 180°, so C = 180° − 40° − 60° = 80°.
The ambiguous case (two possible triangles) can occur with which given information?
Answer: SSA
SSA can produce zero, one, or two triangles, making it ambiguous.