oh, the dread ratio. especially on geometry questions! how dare they not give us numbers!? actually, sometimes ratios can make things easier. the same goes for percents. if you are only looking for the percent by which one thing is bigger than another, the actual numbers don\u2019t matter. just choose easy-to-work-with number(s).<\/p>\n
the ratio of the radii of two circle is 4:5. how much percent less is the area of the smaller circle?<\/p>\n
technically, we don\u2019t even need to find the area of the circle. just square each radii, 4^2 = 16 and 5^2 = 25. how much percent less is 25 than 16? viola! it\u2019s 36% less.<\/p>\n
you might be wondering how that is the case, but notice how the \u03c0 would cancel out in both cases. therefore, we just need to figure out on what makes the two circles different: the length of their radii.<\/p>\n
okay, maybe not too bad. so, here\u2019s one that\u2019s slightly rougher. okay, a lot rougher. do you got what it takes? (see video).<\/p>\n