How can finding the slopes of MN and AB help in proving that MN is the midsegment of triangle ABC?
2 answers:
Answer: The slopes of two parallel lines are equal.
Step-by-step explanation: Let and
be the slopes of lines AB and MN respectively. We know that if the slopes of two parallel lines are equal, then the lines must be parallel. Thus, if we get
, then AB is parallel to MN. Also, if we already have M and N as the mid-points of AC and BC, the with the help of slopes of AB and MN, we arrive at our proof that MN is the mid-segment of Triangle ABC. Please see the figure for details.
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The area of the figure is 40 units. (rounded off from 39.998 units)
Step-by-step explanation:
1. Area of the figure = Area of Rectangle + Area of Parallelogram.
2. Naming points:
Let the rectangle consist of points A(-6,-1), B(-5,-5), C(3,-3) and D(2,1).
Let the parallelogram consist of points C(3,-3), D(2,1), E(2,7) and F(3,3).
3. Each coordinate has a point on the x-axis and a point on the y-axis. We shall refer to these points as x', x'' ,x''' and so on corresponding to the x-axis values of A, B, C and so on in that order till F. For the y-axis points, we will name them in the series of y', y'', y''' and so on.
In simple words, in A(-6,1), x' = -6; y' = -1
4. Formula for finding area:
Area of a rectangle = length (l) × width (w)
Area of a parallelogram = base (b) x height (h)
5. Finding area of the rectangle:
l = AD =
, i.e. AD =
, i.e. AD = √68 = 8.246 (rounded to 3 decimals) = l
Now, w = AB =
, i.e. AB =
, i.e. AB = √17 = 4.123 (rounded to 3 decimals) = w
Area of rectangle = l x w = 8.246 x 4.123 = 33.998 units.
6. Finding area of the parallelogram:
b = DE = 6 units (we can observe this from the graph, i.e. points from 1 to 7 on the y axis)
h = Height is the line drawn perpendicular to the base from point F, which as we can see is 1 unit long.
Hence, Area of parallelogram = b x h = 6 x 1 = 6 units.
7. Now, adding both, we can arrive at the final answer.
Area of the figure = Area of rectangle + Area of parallelogram,
i.e. 33.998 units + 6 units = 39.998 units. (can be rounded off to 40 units)