Skip to main contentSkip to solution

Three decorative lights are hung equidistantly on the edge of a circular swimming pool of radius 15 m. These lights are connected with each other by light wires forming a triangle. What is the perpendicular distance of the wire connecting any two lights from the center of the swimming pool?

Solution

✅ Correct Option: 1

Three decorative lights are hung equidistantly on the edge of a circular swimming pool. This means the lights are equally spaced around the circle, forming an equilateral triangle inscribed in the circle.

The circle has radius R=15R = 15 m (this is the circumradius of the triangle).


For an equilateral triangle inscribed in a circle, the three vertices divide the circle into three equal arcs of 120°120° each.

The perpendicular distance from the center of the circle to any side of the triangle is the inradius of the equilateral triangle.

Solution figure for UGAT Bangalore 2025 Sample Paper QA question 27 (Geometry)

For an equilateral triangle, the relationship between the circumradius RR and the inradius rr is:

r=R2r = \dfrac{R}{2}


Substituting R=15R = 15 m:

r=152r = \dfrac{15}{2}

r=7.5r = 7.5 m


Therefore, the perpendicular distance from the center of the swimming pool to the wire connecting any two lights is 7.57.5 m.

The correct answer is Option 1: 7.5 m

Keyboard Shortcuts

  • Left arrow: Previous question
  • Right arrow: Next question
  • S key: Jump to solution
  • Q key: Jump to question