https://www.gregmat.com/quizzes/quiz/im-overwhelmed-geometry-progress-quiz-7 (Question 8)
I’m not sure why my answer came out differently. It seems like I got the same values for the trapezoid but the actual answer was 88. He also used a strategy in the solution video that was different from the one in the lesson video so I’m a bit confused.
I did the same steps as “A seemingly impossible problem III”.
I made a 45-45-90 triangle. Did 10 / √2 to get x which is 7.07…
With that triangle’s leg being 7.07… that means the other side is also 7.07… which means if the top base is x then the bottom base is x + 7.07… + 7.07…
I set the two bottom bases plus the two sides to be equal to the perimeter and solved and got the top base as being x = 5.428…
Since it said to round to the nearest whole integer I rounded the values down to the top base being 5 and the bottom being 5 + 7 + 7
Got 19+5 divided by 2 which gave me 12
12 x 7 gave me 84.
Is it a rounding problem? If so when am I actually supposed to round the numbers? And I know he typically works with radicals but then having the 45-45-90 triangle legs as 10/√2 would confuse me too much, so I try to use the decimal values when I can.