A student finds the sum of the angle measures in an octagon by multiplying 7 • 180°. What is the student's error?
1 answer:
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Answer:
Step-by-step explanation:
First, to figure out the equation of a line you must find the slope then plug in the coordinates.
In order to find the slope of the equation, you know that it is perpendicular to the equation y = -3x + 7.
Perpendicular slopes are basically reciprocals with opposite signs; you flip the number and give it the opposite symbol.
For example, the perpendicular slope of 2 would -1/2, because flipping the fraction 2/1 is 1/2 and the opposite sign of + would be -.
Therefore, the perpendicular slope of -3 would be 1/3, be 3/1 flipped upside down is 1/3 and the opposite sign of - is +.
Then you plug in the slope into the equation of a line along with the coordinate.
A line is y = mx + b
Since you found the slope, m = 1/3
They also give you the coordinate (3,5), meaning when x = 3, the y =5.
You plug everything into the equation to solve for b:
5 = (1/3)(3) + b
b = 5 - (1/3 * 3) = 5 - 1 = 4
Since you have values for m and b, the equation can now be constructed as
y = 1/3x + 4
We are given a trapezoid TRHY.
Height of the trapezoid = 13 units.
b1 = 21 units and
Area = 215 units squares.
We need to find the length of b2.
We know formula for area of a trapezoid.
Plugging values in formula.
215 = (21+b2)× 13.
215 = 6.5(21+b2)
Dividing both sides by 6.5, we get
33.08 = 21+b2.
Subtracting 21 from both sides, we get
33.08-21 = 21-21+b2
b2 = 12.08.
<h3>Therefore, length of b2 is 12.08 units.</h3>Answer:
- correct answer is C
- Haley incorrectly applied the distributive property
Step-by-step explanation:
If you simplify the given equation, you find it matches choice C.
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Haley's error seems to be failing to distribute the 1/2 properly when she eliminated parentheses. Apparent, she incorrectly decided that ...
1/2(6 -x) ⇒ 3 -x . . . . instead of 3 -1/2x
Then when -x was added to +3x, she got 2x. Had she done it properly, she would have added -1/2x to +3x to get 5/2x.
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<em>Additional comment</em>
It is a common error to "distribute" the factor outside parentheses to the first term only, as Haley apparently did. Another common error is to fail to distribute minus signs properly. The distributive property requires you apply the outside factor to <em>all</em> of the terms inside parentheses.