Grades 11-12 Video Solutions 2025-2025_11-12

Video Transcription

Video Summary

The problem involves finding the perimeter of a shaded region formed by arcs at each vertex of a regular octagon with side 1 cm. Each arc drawn is part of a circle with a 1 cm radius. By leveraging the octagon's symmetry and arc properties, it was determined that the angle subtending each small arc of the shaded region is 15 degrees, due to the calculation of internal angles and subtracting complementary angles. Therefore, the total perimeter of these arcs is 2/3 of the circumference of a full circle (2π), simplifying to the answer: 2π/3 cm (B).

Keywords

perimeter

shaded region

regular octagon

arcs

geometry