Can someone help me with a Geometry question?
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Question

Can someone help me with a Geometry question?
Picture in chat.

jeneshisu · Answer

https://i.imgsafe.org/3794e09746.png

shadowlegendx · Answer

For question number 8, all we need to do is solve for the surface area.

Looking at this equilateral triangle, there are two congruent triangles, two congruent rectangles, and one rectangle off on his own with the dimensions 10x15

jeneshisu · Answer

yes...and

shadowlegendx · Answer

|dw:1477672073844:dw|

shadowlegendx · Answer

At what part do you need help?

shadowlegendx · Answer

Do you know how to find each of the sides?

jeneshisu · Answer

OK, so I found each of the sides already but the answer i got is wrong

jeneshisu · Answer

Do i just add them up afterwards?

shadowlegendx · Answer

Yes

shadowlegendx · Answer

Do you want me to find all the sides, and see if our values match up?

jeneshisu · Answer

yes, thank you

shadowlegendx · Answer

|dw:1477672671047:dw|

Checklist:
Rectangle 1: 150un^2
Rectangle 2 and 3:
Triangle 1 and 2:

The first one our checklist is easy, we just multiply 10 by 15 for 150.

Rectangle 2 and 3 is where it gets difficult, as we need it's width, which is not displayed.

Looking at our right triangle though, it's hypotenuse is the rectangles width, and we have the two side lengths, therefore we can solve for it using Pythagorean's Theorem.

Note: Pythagorean's Theorem only works on right triangles, therefore if you did 8.7^2 + 10^2 = c^2, you would be wrong. The proper use of the theorem would be 8.7^2 + 5^2 = c^2 as I know that the line representing the height, bisects the 10, into two 5's.

$$8.7^2 + 5^2 = c^2$$
$$75.69 + 25 = c^2$$

$$100.69 = c^2$$

Get the square root of both sides, and we get 

$$c = 10.0344406919 \rightarrow 10.03$$
Lets round..

shadowlegendx · Answer

$$10.03 \times 15 \times  2 = 300.9 un^2$$

leenathan · Answer

you should be opening more qustions so that the person answering can get the medals he/she deserves

jeneshisu · Answer

what o.O

jeneshisu · Answer

so the answer is 624?

shadowlegendx · Answer

Checklist:
Rectangle 1: 150un^2
Rectangle 2 and 3: 300.9un^2
Triangle 1 and 2: 

I now only have one more item on the list, which is quite simple

Solving for the two surface areas of the triangle is just a matter of

$$8.7 \times 10 = 87$$

Triangle 1 and 2 = 87

Whilst the formula is

$$A = \frac{ hb }{ 2 }$$

We forgo the division so we don't have to repeat it, as the triangles have the same dimensions

Add up 150, 300.9 and 87, and we get $$537.9 un^2$$

jeneshisu · Answer

Oh, okay

jeneshisu · Answer

Thank you so much!

shadowlegendx · Answer

No problem :)