Which trigonometry function is used to calculate the uncorrected precision approach path indicator (PAPI) distance?

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Multiple Choice

Which trigonometry function is used to calculate the uncorrected precision approach path indicator (PAPI) distance?

Calculating uncorrected PAPI distance relies on the geometry of a right triangle formed by the glide path. The angle of descent (the glide slope) ties together vertical height and horizontal distance through the tangent relationship: tan(angle) = opposite/adjacent. If you know how high you are above the runway (the opposite side) and the glide-slope angle, you find the horizontal distance (the adjacent side) by dividing the height by tan(angle). That makes tangent the natural tool for this calculation. Sine would require the hypotenuse, which isn’t the given measure here, and cosine would also involve the hypotenuse. Cotangent is the reciprocal of tangent, which isn’t the direct path used in this distance calculation.

Calculating uncorrected PAPI distance relies on the geometry of a right triangle formed by the glide path. The angle of descent (the glide slope) ties together vertical height and horizontal distance through the tangent relationship: tan(angle) = opposite/adjacent. If you know how high you are above the runway (the opposite side) and the glide-slope angle, you find the horizontal distance (the adjacent side) by dividing the height by tan(angle). That makes tangent the natural tool for this calculation. Sine would require the hypotenuse, which isn’t the given measure here, and cosine would also involve the hypotenuse. Cotangent is the reciprocal of tangent, which isn’t the direct path used in this distance calculation.

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