Use the Law of Since to find the angle C B 60degree b 7cm

Use the Law of Since to find the angle C: B = 60degree, b = 7cm, c = 4cm find the third side of the triangle given by: b = 5in, c = 7in, a = 30degree Find area of a triangle having two sides 8 and 6, and an included angle of 60degree. Find the area of triangle have three sides 10, 18, and 16. For example 1) to 3), use these complex numbers: v = 2i-3j, w= i-2j 2w-3v w-v w + v Find magnitude of: v = -4i + 3j

Solution

1) B = 60 deg ; b= 7 cm; c = 4cm

Use sine rule: b/sinB = c/sinC

7/sin60 = 4/sinC

sinC = 4*sin60/7 = 0.4948

C = sin^-1(0.4948) = 29.66 deg

2) b = 5inch ; c= 7 inch ; A = 30 deg

a^2 = b^2 +c^2 -2b*ccos30

= 5^2 +7^2 - 2*5*7cos30

= 13.378

a = sqrt(13.378) = 3.65 inch