What is the length of the outside stringer for a circular stair covering 1/2 a circle if the width is 1100 mm and the inside radius is 2500 mm?

The correct approach to determine the length of the outside stringer for a circular stair that covers half a circle involves using the arc length formula. The length of the outside stringer can be calculated by considering that it effectively forms the outer arc of the circular stair.

To find the length of the outside stringer, one must first calculate the radius of the outside stringer. This is done by adding the width of the stair to the inside radius. In this case, the inside radius is 2500 mm, and the width of the stair is 1100 mm, making the outside radius 3600 mm (2500 mm + 1100 mm).

Using the arc length formula, which is given by (L = r \times \theta), where (L) is the arc length, (r) is the radius, and (\theta) is the angle in radians, the arc length (or the length of the outside stringer) for 1/2 a circle (which is (\pi) radians) can be calculated.

Thus, the length of the outside stringer becomes:

[

L = 3600 , \text{mm} \times \pi

]