What is the slope of a vertical line?

The slope of a vertical line is undefined. This is because the calculation of slope involves dividing the change in y by the change in x (rise over run). For a <a href="https://www.wikiwhat.page/kavramlar/vertical%20line">vertical line</a>, the change in x is always zero. Division by zero is undefined in mathematics. Therefore, the <a href="https://www.wikiwhat.page/kavramlar/slope">slope</a> of a vertical line is considered undefined.