# Python: Test whether two lines PQ and RS are parallel

## Python Basic - 1: Exercise-43 with Solution

Write a Python program to test whether two lines PQ and RS are parallel. The four points are P(x1, y1), Q(x2, y2), R(x3, y3), S(x4, y4).

**Input: **

x1,y1,x2,y2,x3,y3,xp,yp separated by a single space

**Sample Solution**:

**Python Code:**

```
print("Input x1,y1,x2,y2,x3,y3,xp,yp:")
x1, y1,x2, y2, x3, y3, x4, y4 = map(float, input().split())
print('PQ and RS are parallel.' if abs((x2 - x1)*(y4 - y3) - (x4 - x3)*(y2 - y1)) < 1e-10 else 'PQ and RS are not parallel')
```

Sample Output:

Input x1,y1,x2,y2,x3,y3,xp,yp: 2 5 6 4 8 3 9 7 PQ and RS are not parallel

**Flowchart:**

**Python Code Editor:**

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