Grades 9-10 Video Solutions 2026-2026_9-10

Video Transcription

Video Summary

The diagram uses two congruent rectangles, \(ABCD\) and \(DCEF\), to compare areas. Instead of finding \(\triangle ACO\) directly, the solution subtracts surrounding shapes from rectangle \(ABEF\). It breaks the leftover region into a right triangle and two trapezoids, then computes each in terms of \(XY\), the area of \(ABEF\). After simplifying, the area of \(\triangle ACO\) is \(\frac{XY}{4}\), which is one-fourth of rectangle \(ABEF\). Therefore, the fraction of the area of rectangle \(ABF\) that is triangle \(ACO\) is \(\boxed{\tfrac14}\).

Keywords

congruent rectangles

area comparison

triangle ACO

trapezoids

one-fourth area