# What is the surface area of my fish tank

• April 15th, 2014, 10:05 AM
penfold
What is the surface area of my fish tank
Hi there i am sorry for posting this but i couldn`t think of where else to go ,my question is ... i have a five sided fish tank 16x16x4.5x4.5x16. in other words 3 sides are 16 and 2 sides are 4.5. what is the surface area in inches please .just look upon it as helping out some fish who live with a thick guy.thanks :smile:
• April 15th, 2014, 10:13 AM
RedPanda
Do you mean the surface area of the glass?

If so, simply work out the surface area for each pane and add them up.
• April 15th, 2014, 10:20 AM
Strange
Quote:

Originally Posted by RedPanda
Do you mean the surface area of the glass?

If so, simply work out the surface area for each pane and add them up.

I assume it is the surface area of the water. (Having had to do this for my pond several times.)

Quote:

Originally Posted by penfold
just look upon it as helping out some fish who live with a thick guy.

:)

How about drawing a (scaled) diagram and then divide it into triangles, which should be easier to calculate (In other words, I am too lazy busy to do it for you!)
• April 15th, 2014, 10:21 AM
PhDemon
The easiest way to do it is to divide your pentagon into triangles. To help us work it out provide a diagram (or at least the angles between the sides) it would take some time to figure out the shape (and how to split it into triangles) with just the lengths you have provided.

If you want to have a go yourself here is how to do it: Irregular multi sided polygon

Ninja'd by Strange (again), but I got in before KALSTER ;)
• April 15th, 2014, 10:23 AM
KALSTER
If you are talking about the bottom of the tank, we'll need some angles as well.

Ninja'd twice.
• April 15th, 2014, 10:54 AM
penfold
[IMG]http://i60.tinypic.com/1zdvo5t.jpg[/IMG]LOL sorry this is the best i could do ,i had to borrow the superman logo but that is the shape looking down on the tank . yes it is the water surface area . thanks EDIT where the two sides which are 16 inch long each meet is a right angle 45 degrees that is where it goes into the corner of a wall . thanks
• April 15th, 2014, 11:05 AM
Harold14370
If that's drawn to scale, you have a square of 16 inches on each side, minus a triangle with a base of 11.5 inches and a height of 11.5. The area of the square is 16*16=256. The area of the triangle is .5*11.5*11.5=66.125. The area of the tank is 189.875.
• April 15th, 2014, 11:15 AM
PhDemon
I split it into two right angled triangles (assuming the angles at the bottom and top of your picture are 90 degress) with an isoceles triangle in the middle. The areas of the right angled trianlges are 0.5*16*4.5 = 36 sq in each, the height of the isoceles triangle is sqrt(16.62^2-8^2) 9from Pythagoras theorem to get the hypotenuse of the right angled triangles then again to get the height if the isoceles triangle (which is 14.57 in) which gives an area for the isoceles triangle of 0.5*16*14.57 = 116.56 sq in.

Total area = 116.56 + 36 +36 = 188.56 (pretty close to Harolds, withion 1% may be some rounding errors)
• April 15th, 2014, 11:47 AM
penfold
thanks guys ,the picture is not to scale it is only a rough guide, i know there are 3 right angles . the figures are correct . i think it is based on a square, side 1 and 2 are both 16 inch long each, but side 3 and 4 are only 4.5 inch long and are then joined by side 5 which is 16 inch long.
• April 15th, 2014, 11:51 AM
Harold14370
It doesn't change my answer, as long as you have the 3 90 degree angles and dimensions as shown.
• April 15th, 2014, 12:46 PM