Lösung 2.2:9a
Aus Online Mathematik Brückenkurs 1
K (Lösning 2.2:9a moved to Solution 2.2:9a: Robot: moved page) |
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+ | We can start by drawing the points | ||
+ | <math>\left( 1 \right.,\left. 4 \right)</math>, | ||
+ | <math>\left( 3 \right.,\left. 3 \right)</math> | ||
+ | and | ||
+ | <math>\left( 1 \right.,\left. 0 \right)</math> | ||
+ | in a coordinate system and draw lines between them, so that we get a picture of how thetriangle looks. | ||
+ | |||
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[[Image:2_2_9_a-1(2).gif|center]] | [[Image:2_2_9_a-1(2).gif|center]] | ||
- | + | ||
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+ | |||
+ | If we now think of how we should use the fact that the area of a triangle is given by the formula | ||
+ | |||
+ | Area= | ||
+ | <math>\frac{1}{2}</math> | ||
+ | (base)∙(height), | ||
+ | |||
+ | it is clear that it is most appropriate to use the edge from | ||
+ | <math>\left( 1 \right.,\left. 0 \right)</math> | ||
+ | to | ||
+ | <math>\left( 1 \right.,\left. 4 \right)</math> | ||
+ | as the base of the triangle. | ||
+ | The base is then parallel with the y-axis and we can read off its length as the difference in the | ||
+ | |||
+ | <math>y</math> | ||
+ | -coordinate between the corner points | ||
+ | <math>\left( 1 \right.,\left. 0 \right)</math> | ||
+ | and | ||
+ | <math>\left( 1 \right.,\left. 4 \right)</math>, i.e. | ||
+ | |||
+ | base | ||
+ | <math>=4-0=0</math>. | ||
+ | In addition, the triangle's height is the horizontal distance from the third corner point | ||
+ | <math>\left( 3 \right.,\left. 3 \right)</math> | ||
+ | to the base and we can read that off as the difference in the | ||
+ | <math>x</math> | ||
+ | -direction between | ||
+ | <math>\left( 3 \right.,\left. 3 \right)</math> | ||
+ | and the line | ||
+ | <math>x=1</math>, i.e. | ||
+ | |||
+ | height | ||
+ | <math>=3-1=2</math>. | ||
+ | |||
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[[Image:2_2_9_a-2(2).gif|center]] | [[Image:2_2_9_a-2(2).gif|center]] | ||
- | + | ||
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+ | |||
+ | Thus, the triangle's area is | ||
+ | |||
+ | Area= | ||
+ | <math>\frac{1}{2}</math> | ||
+ | (base)∙(height) | ||
+ | <math>=\frac{1}{2}\centerdot 4\centerdot 2=4</math> | ||
+ | = area units. |
Version vom 12:56, 18. Sep. 2008
We can start by drawing the points
1
4
3
3
1
0
If we now think of how we should use the fact that the area of a triangle is given by the formula
Area=
it is clear that it is most appropriate to use the edge from
1
0
1
4
1
0
1
4
base
3
3
3
3
height
Thus, the triangle's area is
Area=