ASIN function: calculate ramp incline angles from rise and sloped length

When you measure ramp surface length instead of horizontal ground run

Inspectors checking loading ramps or staircases with a tape laid directly along the sloped surface measure vertical rise (opposite) and sloped ramp length (hypotenuse). Their ratio rise / length equals sin(theta), so ASIN(number) returns the incline angle in radians between -pi/2 and +pi/2 (-90° to +90°).

A 6-meter ramp rising 3 meters has ratio 0.5 and angle DEGREES(ASIN(3/6)) = 30°. A 12-meter ramp rising 1 meter gives DEGREES(ASIN(1/12)) = 4.7802°.

Calculate incline angle in degrees

Wrap ASIN in DEGREES and ROUND so inspection sheets show clear decimal degrees rather than raw radians.

=ROUND(DEGREES(ASIN(A2 / B2)), 4)

Guard vertical rise exceeding sloped length

Vertical rise can never exceed total sloped length (|A2| <= B2). Checking ABS(A2) > B2 catches swapped measurements cleanly.

These examples assume a strictly positive measured length. Validate that length is greater than zero before dividing; a zero length makes the ratio undefined.

=IF(ABS(A2) > B2, "Rise exceeds length", ROUND(DEGREES(ASIN(A2 / B2)), 4))

Further reading

• Microsoft Support — ASIN function