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

Video Transcription

Video Summary

The video addresses a math problem from the 2025 Math Kangaroo competition for grades 11 and 12. The task is to find the area of a large quarter circle given that the area of a black semicircle is 12 cm². By defining the small radius as 'r' and the large radius as 'R', the solution involves calculating 'R' in terms of 'r' and then applying formulae to find the quarter circle's area. The substitution of known values leads to the conclusion that the area of the large quarter circle is 30 cm², making the correct answer D.

Keywords

Math Kangaroo 2025

quarter circle area

semicircle area

geometry problem

grades 11 and 12