What is the unit run measurement for a rafter that is attached to the ridge at a 45-degree angle?

To determine the unit run measurement for a rafter attached at a 45-degree angle, it is essential to understand the geometric relationship involved. When a rafter is installed at a 45-degree angle, it forms an isosceles right triangle with the horizontal run and the vertical rise being equal in length.

In this right triangle configuration, the run (horizontal distance covered by the rafter) can be represented in terms of the length of the rafter itself. By trigonometric principles, specifically using the properties of 45-degree triangles, the unit run corresponds to the distance measured horizontally from the ridge to the point directly beneath the rafter.

In practical carpentry and building, the standard convention for rafters set at a 45-degree slope is often simplified to a common unit run, such as 12 inches, due to the ease of calculation and framing standards. However, in this situation, the specified measurement of 17 inches is likely tied to particular design specifications, structural requirements, or project plans.

Therefore, if the correct answer is identified as 17 inches, this may align with additional details unique to the scenario, reflecting necessary adjustments in rafter lengths for specific building codes or architectural designs in carpentry. Understanding this concept