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Tag! dear tutors and supporters: I am attaching the problemm. I draw a line and I can see I have a rectangle and a triangle now. is this a good way to find the area of this trapezoid? Danke im Voraus. Für alle, die mir helfen möchten (automatisch von OnlineMathe generiert): "Ich möchte die Lösung in Zusammenarbeit mit anderen erstellen." |
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I am going to post some work here and see if it is good I am gonna find the area of the triangle first. I have two sides the hypotenuse and a side hypothenuse= cm ? √51=√b this is the area of the triangle now I will find the area of the rectangle and add the two together. is this right? |
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Decomposing the trapezoid into a rectangle and a triangle, as you did, is certainly a good way to determine the total area. Unfortunately, the creator of the problem has made a serious mistake, because he has given too many dimensions. The side of your triangle, which you called must be (difference of the lengths and . From this we can calculate the length of the hypotenuse with (and not cm). So depending on which of the four dimensions given you omit in your calculation you will arrive at a different total area. I guess its best to omit the cm which leads to a total area of . |
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The picture has a mistake if the lower side is 12cm and the upper side 18cm the difference, your side should be 6cm but your calculation with Pythagoras for is also right . having the area is not like you suggest but so if the 18cm are right it would be 6*7cm^2 and then the rectangle with Pythagoras you find 7*7,14cm^2 so either the 18cm or the cm are wrong, calculating with the formula for trapezoids you get the area with b=6cm ledum |
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but I thought the hypothenuse side =10cm. why is it not the hypothenuse? I'm in doubt here. |
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The side you call IS the hypotenuse, but if you rely on the given measures and its length can't be . So EITHER of the four given length or must be omitted and it seems that its best to omit the cm. ![]() |
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Verständigungs-Stütze: |
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I get it now. I solved for and got cm like you. okay, now have cm cm cm I am adding all this up to find the area Area of the triangle cm^2 area of the rectangle cm^2 now, (cm^2) Area of the whole trapezoid cm^2 is this correct? thanks ledum as well. If I Did not reply directly to you was becasue your comment was similar to Roman |
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Area of the triangle cm^2 No! Forget about the side You don't need it. Look at the sketch I attached at the end of my last post. Since you have given both cathets, you can simply calculate the area with BTW, another way to get the total area of the trapezoid would be to duplicate the whole trapezoid and compose a rectangle from the two pieces with the side lenghts 7 cm and . You sure can calculate the area of this rectangular and divide it by 2 ;-) ![]() |
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oh okay, I see it. cm^2 now to find the area of the rectangle cm^2 so, The trapezoid's are is cm^2 cm^2 cm^2 right?. thanks, Nuele, too. |
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thanks, N8eule!. |
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right?. No! Now your area of the rectangle is wrong. But you already knew the correct result of 7 times at :-) Combining the correct results should given you the already mentioned above. BTW, if you type a space between "c" and "m" when typing "7 cm^2" in text mode, you get the desired |
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I like that way best!. thanks. |
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I like that way best!. thanks. |
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I like that way best!. thanks. |
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Roman you said the area of the rectangle is wrong. can you explain why? I did not get that. |
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oh see it. it is the wrong calculation |