Just wondering if anyone knows why the surface length is generally more than the length of the hypotenuse when measuring regular surfaces e.g. roofs? If I drop a line on a roof I find that the surface length is more than hypotenuse calculated either by myself or the surface/distance/slope app. I can understand if this was on the ground where the surface is irregular but it seems odd when it’s a man made structure like this.
Any thoughts welcome!