Slope Calculator

Slope Calculator

Find the slope between two points (x₁, y₁) and (x₂, y₂)

Point 1

Point 2

How To Calculate Slope

Step 1: Identify Two Distinct Points

Select points P1(x₁, y₁) and P2(x₂, y₂) on the line to be analyzed.

Why: Slope is defined as the ratio of vertical to horizontal change between two points.

Step 2: Ensure Points Are Different

Verify that (x₁, y₁) ≠ (x₂, y₂); if they're identical, no unique slope exists.

Why: Different points are required for the denominator (x₂ - x₁) to be non-zero.

Step 3: Calculate Vertical Change (Rise)

Subtract: rise = y₂ - y₁ (change in y-coordinate).

Why: Rise measures how far the line goes up or down between the points.

Step 4: Calculate Horizontal Change (Run)

Subtract: run = x₂ - x₁ (change in x-coordinate).

Why: Run measures the horizontal distance; combining with rise yields the slope ratio.

Step 5: Divide to Find Slope; Convert to Angle

m = rise / run; then θ = arctan(m) to get the angle of inclination.

Why: Slope as a decimal is useful algebraically; angle provides geometric intuition.

Detailed Example

Scenario: Find the slope between points (2, 3) and (5, 9).
Step 1 - Identify Points: P1 = (2, 3), P2 = (5, 9).
Step 2 - Verify Differences: (2, 3) ≠ (5, 9) ✓
Step 3 - Calculate Rise: y₂ - y₁ = 9 - 3 = 6 (line goes up 6 units).
Step 4 - Calculate Run: x₂ - x₁ = 5 - 2 = 3 (line goes right 3 units).
Step 5 - Find Slope & Angle: m = 6/3 = 2. Then θ = arctan(2) ≈ 63.43°.
Verification: Slope 2 means for every 1 unit right, line rises 2 units. 63.43° is steeper than 45° (which is m=1). ✓
Result: The slope is 2 (or 200% grade); the angle is approximately 63.43°.
Interpretation: A positive slope indicates an upward-slanting line (left to right); larger magnitude means steeper incline.

Formula

The slope (m) of a line passing through two points is the "rise over run":m = (y₂ - y₁) / (x₂ - x₁)

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