Grades 7-8 Video Solutions 2021-video 2021 7-8/2

Video Transcription

Question 2. The figure shows three concentric circles with four lines passing through their common center. What percentage of the figure is shaded? We  take a look at the circle and then we draw the lines and we shade it exactly as it is shaded in the picture. To solve this problem we can start by moving  around the shaded regions to be closer together. So we take the three pieces and move them over to the top and do the same with the one piece in the middle  and then we just have two more pieces that we move over. Once we have this it is clear to see that half of the circle is shaded and half of it is not. This  means that our answer is E, 50%.

Video Summary

Question 2. The figure shows three concentric circles with four lines passing through their common center. What percentage of the figure is shaded? We take a look at the circle and then we draw the lines and we shade it exactly as it is shaded in the picture. To solve this problem we can start by moving around the shaded regions to be closer together. So we take the three pieces and move them over to the top and do the same with the one piece in the middle and then we just have two more pieces that we move over. Once we have this it is clear to see that half of the circle is shaded and half of it is not. This means that our answer is E, 50%.

Keywords

concentric circles

shaded percentage

geometry problem

circle sectors

visualization