Considering The Cosine Rule of any triangle ABC, the possible measures of angle A includes
A. angle A is obtuse
B. angle A is acute
C. angle A is right-angle
D. all of above
For the Cosine Rule of any triangle ABC, the b² is equal to
A. a² - c² + 2ab cos A
B. a³ + c³ - 3ab cos A
C. a² + c² - 2ac cos B
D. a² - c² 4bc cos A
For the Cosine Rule of any triangle ABC, the c² is equal to
A. c² + a² + 2ac cos C
B. a² + b² - 2ab cos C
C. a² + b² + 2ab cos A
D. a² - b² + 2ab sin A
In a triangle ABC, if angle A = 72° , angle B = 48° and c = 9 cm then the Ĉ is
A. 69°
B. 66°
C. 60°
D. 63°
The sine rule for a triangle states that
A. a/sin A = b/sin B = c/sin C
B. sin A/a = sin B/b = sin C/c
C. a/sin A + b/sin B + c/sin C
D. 2a/sin A = 2b/sin B = 2c/sin C
By expressing the sin 125° in terms of trigonometrical ratios, the answer will be
A. sin 65° = 0.9128
B. sin 55° = 0.8192
C. sin 70° = 0.5384
D. sin 72° = 0.1982