Grades 9-10 Video Solutions 2013-Level 9&10 Video Solutions 2013 problem11

Level 9&10 Video Solutions 2013 problem11

Video Transcription

Video Summary

The problem involves determining the measure of angle RKM after an equilateral triangle KZM is rotated 130 degrees clockwise to become triangle RZT. Angle RKM, using properties of isosceles and equilateral triangles, is calculated by subtracting the 25-degree angles from the 60-degree angle of the original equilateral triangle KZM. The triangle's symmetry indicates angles KRZ and RKZ both measure 25 degrees. Hence, angle RKM equals 60 degrees minus 25 degrees, resulting in 35 degrees. The correct answer is option D, 35 degrees.

Keywords

equilateral triangle

angle calculation

triangle rotation

isosceles triangle

geometry problem