Grades 7-8 Video Solutions 2022-2022_7-8

Video Transcription

Video Summary

The problem involves calculating the size of angle BAC in an isosceles triangle ABC that is further divided into smaller isosceles triangles. By denoting angle BAC as alpha and analyzing the geometric properties and symmetry, it is established that all interior angles involving alpha and beta sum up consistently. Initially expressed through these relationships, the equation 5 alpha equals 180 is derived from summing the angles around point B and then solving for alpha. Calculating this gives alpha = 36 degrees, which is the size of angle BAC. The solution employs symmetry and angle sum properties of triangles.

Keywords

isosceles triangle

angle calculation

geometry

symmetry

angle BAC