# I need help with this one (area of a triangle)

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#### Shogun

##### New member
The lenght of the hypotenuse of an isoscoles right triangle is 30 meters. Find the area of the triangle. Round to the nearest tenth.

I have tried solving this problem and am completely stumped. Can someone please help me out with this. I tried solving and this is what I did. I just don't know how to do this at all.

A^2 + B^2 = C^2

2A^2 = C^2
----------------
2 2

A^2 = C^2
-------
2

#### stapel

##### Super Moderator
Staff member
I think you have done the following:

. . . . .Let A, B, and C be the lengths of the sides of the
. . . . .right triangle, with A = B, and C the hypotenuse.
. . . . .Then:

. . . . .A<sup>2</sup> + B<sup>2</sup> = C<sup>2</sup>

. . . . .But since A = B, we have:

. . . . .A<sup>2</sup> + A<sup>2</sup> = C<sup>2</sup>
. . . . .2 A<sup>2</sup> = C<sup>2</sup>

I'm not sure what you did after that, however...?

Note that the exercise gives you the length of C. Try plugging this in. Then solve for A.

Draw the triangle, and note the height and base. Then apply the "area of a triangle" formula.

Eliz.

#### Shogun

##### New member
That is where my problem lies in solving for A.

Staff member
C = 30 m?

#### Shogun

##### New member
I need help solving for A because my book does not show me how to do it. I am a distance learner so I do not have a teacher/instructor to ask.

#### pka

##### Elite Member
It appears to me as if you need to do some very basic practice problems in basic algebra.
$$\displaystyle \begin{eqnarray*} A^2 + A^2 & = & 30^2 \\ 2A^2 & = & 900 \\ A^2 & = & 450 \\ A & = & \sqrt {450} \\ \end{array}$$

#### Shogun

##### New member
Thanks for the help although your last comment was uncalled for. I said I had never seen a problem that looked like this one before so obviously it is not basic algebra for me. The help is appreciated and that is why I come to this forum but the unwanted comments are not.

#### tkhunny

##### Moderator
Staff member
Wrong answer. You came here to get correct answers. Being honest with you is part of that. No one has attempted to insult you.

So, what other mathematics can we learn?

#### stapel

##### Super Moderator
Staff member
Shogun said:
Thanks for the help although your last comment was uncalled for.
It is regrettable that the tutor's gentle suggestion has offended you, but the suggestion remains valid. Either you learned this prerequisite material in an earlier course and need now to review it, or else the school failed to provide you with that necessary prerequisite content.

We cannot know which is the case. The former is both much more common and much easier to fix, and thus was the tutor's assumption. If instead the latter, as you say, is the case, then you would be well advised to have a serious talk with your instructor, as we are just not able to repair the "holes" in your background within this environment.

I apologize for our confusion. My best wishes to you.

Eliz.

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