When you arrange the N points in sequence around the polygon (clockwise or counterclockwise), the area is half the magnitude of the sum of the determinants of the points taken pairwise. The N determinants will also include the one involving the last point and the first one.
For example, consider the vertices of a triangle: (1,1), (2,3), (3,-1). Its area can be computed as
(1/2)*|(1*3-1*2) +(2*-1-3*3) +(3*1-(-1)*1)|
= (1/2)*|1 -11 +4| = 3
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Given Information
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Total number of people = 165
Adult = $6
Child = $2
Total collected = $618
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Assumptions
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Let x be the number of adults and y be the number of children
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Form equations
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Total number of people
x + y = 165
Total amount collected
6x + 2y = 618
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Ans: The two equations are x + y = 165 and 6x + 2y = 618
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The question is not asking for it but if you need to solve the equation to find the answer to x and y
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Present the two equations and solve for x and y
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x + y = 165 ------------------------- (eqn 1)
6x + 2y = 618 ------------------------- (eqn 2)
(eqn 1) :
x + y = 165
x = 165 - y ------------------------- substitute into (eqn 2)
6(165 - y) + 2y = 618
990 - 6y + 2y = 618
4y = 990 - 618
4y = 372
y = 93 ------------------------- substitute into (eqn 1)
x + y = 165
x + 93 = 165
x = 165 - 93
x = 72
x = 72 and y = 93
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Ans: 72 adults and 93 children
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X° + 123° + 90° = 360° (angles at a point)
x° = 360° - 90° -123°
x° = 147°
The answer of x is 147°
Hope I can help you :)
You first need to change the percent into a decimal then multiply by 80 to get your answer
.35*80=28
