Question

Write a Python3 program to check if 3 user entered points on the coordinate plane creates a triangle or not. Your program needs to repeat until the user decides to quit, and needs to deal with invalid inputs.

Answer 1

Answer:

tryagain = "Y"

while tryagain.upper() == "Y":

    x1 = int(input("x1: "))

    y1 = int(input("y1: "))

    x2 = int(input("x2: "))

    y2 = int(input("y2: "))

    x3 = int(input("x3: "))

    y3 = int(input("y3: "))

    area = abs(x1 *(y2 - y3) + x2 * (y1 - y3) + x3 * (y1 - y2))

    if area > 0:

         print("Inputs form a triangle")

    else:

         print("Inputs do not form a triangle")

    tryagain = input("Press Y/y to try again: ")

Explanation:

To do this we simply calculate the area of the triangle given that inputs are on plane coordinates i.e. (x,y).

If the area is greater than 0, then it's a triangle

If otherwise, then it's not a triangle.

This line initializes iterating variable tryagain to Y

tryagain = "Y"

while tryagain.upper() == "Y":

The following lines get the coordinates of the triangle

    x1 = int(input("x1: "))

    y1 = int(input("y1: "))

    x2 = int(input("x2: "))

    y2 = int(input("y2: "))

    x3 = int(input("x3: "))

    y3 = int(input("y3: "))

This calculates the area

    area = abs(x1 *(y2 - y3) + x2 * (y1 - y3) + x3 * (y1 - y2))

This checks for the condition stated above.

    if area > 0:

         print("Inputs form a triangle") This is printed, if true

    else:

         print("Inputs do not form a triangle") This is printed, if otherwise

    tryagain = input("Press Y/y to try again: ") This prompts the user to try again with another set of inputs