calculate the angles of a triangle with sides of length 4m, 5m and 7m.

Question

the quation demands the angle and minutes but i don`t know how to calculate the minutes. may you please show the formula step by step.

 

Answer 1

The mesurements of triangle a = 4m,b = 5m and c = 7m

Solve the triangle by using SSS rule

cosA = (b² + c²  - a²)/2bc

cosA = (5² + 7²  - 4² )/2(5)(7)

cosA = (25 + 49 - 16)/70

cosA = 58/70

A = cos^-1(58/70)

A = 34.04°

1 degree = 60 minutes

To convert the degrees in minutes just multiply by 60.

A = 34.04*60

A = 2042.4'

cosB = (c² + a²  - b²)/2ca

cosB = (7² + 4²  - 5² )/2(7)(4)

cosB = (49 + 16 - 25)/56

cosB = 40/56

B = cos^-1(40/56)

B = 44.41°

B = 44.41*60

B = 2664.6'

The sum of angles in traingle = 180°

C = 180 - (A + B)

C = 180 - (34.04 + 44.41 )

C = 180 - 78.45

C = 101.55°

C = 6093'