So in finding the area of the square where the part of the yard that is not covered, first is to calculate the are of both then subtract the two and the are for the circle is pi*r^2 so it means pi*(4x)^2 then for the are of square the formula is A^2 and its (20x)^2, and i think the best answer would be 20X^2-(pi*4x^2)
Vertices are formed when 2 sides come together on a polygon. So they are basically corners. The smallest amount of sides a polygon has is 3, which would be a triangle. And triangles have 3 corners, because with a triangle, each side touches the other two. So the minimum number of vertices needed to form a polygon would be 3.
Answer:
The easiest way I can think of to show someone who is not very mathematically inclined that the calculation is wrong (other than using a scientific calculator) is this:
Explain that one half contains four eighths - you can visualize this very simply with a pie chart.
Then tell Anna that mathematically speaking this translates to the equation:
1/2 = 4 * 1/8
Now, if ONE half is equal to four times ONE eighths, then SEVEN halves is equal to four times SEVEN eighths - basically, you just multiply both sides by 7:
7/2 = 4 * 7/8
Now, compare this to the equation proposed by Anna:
7/2 = 1½ * 7/8
I guess, at this point it will be easy to convince Anna that 1½ is not 4, and therefore her equation is faulty.
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Alternatively, if she's sound with fractions you could also tell her that to get from 7/8 to 7/2 you will need a factor which only affects the denominator as the numerator stay the same. The factor that turns 8 into 2 is 1/4 but since this takes place in the denominator we need the reciprocal to turn 1/8 into 1/2 - and the reciprocal of 1/4 is of course 4. At which point we've arrived at the same place of argumentation as before (which is that 4 ≠ 1½).
Step-by-step explanation:
hope this helps :)