Length of remaining two sides of a Triangle from a given side and its adjacent angles

Given the length of a side a of a triangle and its adjacent angles B and C, the task is to find the remaininig two sides of triangle.

Input: a = 5, B = 62.2, C = 33.5
Output: 4.44, 2.77
The remaining two sides of the triangle are b = 4.44488228556699 and c = 2.7733977979419038

Input: a = 12, B = 60, C = 30
Output: 10.39, 5.99
The remaining two sides of the triangle are b = 10.392304845413264 and c = 5.999999999999999


  1. The remaining angle can be calculated by the angle sum theoram in a triangle:
  2.  A = 180 - B - C

  3. The other two sides of triangle can be computed using sine formula:
  4. a/sin A = b/sinB = c/sinC = constant

Below is the implementation of the above approch:






# Python 3 program for above approach
import math
# Function for computing other
# 2 side of the trianlgle
def findSide(a, B, C):
    # computing angle C
    A = 180-C-B
    # converting A in to radian
    radA = math.pi *(A / 180)
    # converting B in to radian
    radB = math.pi *(B / 180)
    # converting C in to radian
    radC = math.pi *(C / 180)
    # computing length of side b
    b = a / math.sin(radA)*math.sin(radB)
    # computing length of side c
    c = a / math.sin(radA)*math.sin(radC)
    return b, c
# driver program
a = 12
B = 60
C = 30
# calling function
b, c = findSide(a, B, C)
print(b, c)



10.392304845413264 5.999999999999999

Time Complexity: O(1)
Auxillary Space: O(1)

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