Hackerrank Solution: Find Angle MBC in Python [4 Methods]

Question: Find Angle MBC - Hacker Rank (Python)

ABC is a right triangle, 90^o at B.
Therefore, angle ABC = 90^o.
Point M is the midpoint of hypotenuse AC.

You are given the lengths AB and BC.
Your task is to find the angle MBC in degrees.

Input format:

The first line contains the length of side AB.
The second line contains the length of side BC.

Constraints:

• 0 < AB <= 100
• 0 < BC <= 100
• Lengths AB and BC are natural numbers.

Output format:

Output angle MBC in degrees.

Note: Round the angle to the nearest integer.

Examples:
If angle is 56.5000001°, then output 57°.
If angle is 56.5000000°, then output 57°.
If angle is 56.4999999°, then output 56°.

Sample input:

10
10

Output:

45

 

Possible solutions

As we will be provided by the sides and then we have to find the angle. For this question, we can come up with multiple solutions.

• Using math module
• Using math module: Alternative solution
• Using math module with fewer lines of code
• Alternative solution

 

Solution-1: Using math module

The math module is a standard module in Python and is always available. To use mathematical functions under this module, you have to import the module using import math. Let us import the math module and find the angle using the given sides of the triangle.

# importing the module
import math

# taking the input from user
ab = float(input())
bc = float(input())

# finding the distance 
ac = math.sqrt((ab*ab)+(bc*bc))
bm = ac / 2.0
mc = bm

# equalizing the sides 
b = mc
c = bm
a = bc

# where b=c
# finding the angle in radian
angel_b_radian = math.acos(a / (2*b))

# converting the radian to degree
angel_b_degree = int(round((180 * angel_b_radian) / math.pi))

# printing with degree
print(angel_b_degree,'\u00B0',sep='')

Input:

10
10

Output:

45°

As you can see, we get the 45-degree angle as required.

 

Solution-2: Using a math module: Alternative solution

Now, we will transform the above code into fewer lines as an alternative solution shown below:

# importing the math module
import math

# taking input of the sides
ab=int(input())
bc=int(input())

# finding the distance
ca=math.hypot(ab,bc)
mc=ca/2

# finding the angle
bca=math.asin(1*ab/ca)
bm=math.sqrt((bc**2+mc**2)-(2*bc*mc*math.cos(bca)))
mbc=math.asin(math.sin(bca)*mc/bm)

# printing the angle
print(int(round(math.degrees(mbc),0)),'\u00B0',sep='')

Input:

10
10

Output:

45°

As you can see, we get 45 degrees which was required in the sample.

 

Solution-3: Using Math module with fewer lines

We can even reduce the number of lines to make our code more optimized and readable.

# importing math
import math

# taking inputs
a = int(input())
b = int(input())

# finding distace and angle
M = math.sqrt(a**2+b**2)
theta = math.acos(b/M )

# printing the angle
print(int(round(math.degrees(theta),0)),'\u00B0',sep='')

Input:

10
10

Output:

45°

As you can see, we were able to get the same result using fewer lines of code.

 

Solution-4: Alternative Solution

Now, we will use another simple method to calculate the angle.

# importing math
import math

# taking input from user
AB,BC=int(input()),int(input())

# calculating distance
hype=math.hypot(AB,BC)      

# calculating the angle
res=round(math.degrees(math.acos(BC/hype))) 

# the 176 represents the degree symbol
degree=chr(176)                          
print(res,degree, sep='')

Input:

10
10

Output:

45°

The char(176) in the code represents the degree sign.

 

Summary

As we were supposed to find the angle of a triangle when the sides were given. In this short article, we come up with multiple solutions to solve the FIND ANGLE question from Hacker Rank.

 

References

Python math
Question on Hacker rank: Find Angle MBC in Python

 

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