Check my integration work and help with problem 25

[EggNest]

Hello everyone,

I need help with a couple of problems, right now I'm focusing on number 25.

http://img24.exs.cx/img24/2291/probs.gif

Also, if any of you have time, could you please tell me if I have missed any so far. Thanks.

22. A= 3768.2 units^2
23. A= 25.3 units^2
24. A= 5.4 units^2

And now if I could just get some help with the others...

 

[arildno]

Now, you've got a square with the diagonal given, right?
So, what's your problem, exactly?

 

[EggNest]

Now, you've got a square with the diagonal given, right?
So, what's your problem, exactly?

I need help going about finding the length of the sides

 

[arildno]

Sure enough, but:
1) You've got a square, right?
So, how does then the vertical side compare in length to the horizontal side?
2) Try to set up Pythagoras' theorem with the diagonal as the hypotenuse..

 

[EggNest]

The length of all the sides would be 7.5 sqrt(2) right?

 

[Tom McCurdy]

We have C from Pythagoras' therom
$$a^2 + b^2 = c^2$$

however for a square
$$a=b$$

so
$$a^2 + a^2 = c^2$$
$$2a^2=c^2$$

$$2a^2=15^2$$
$$2a^2=225$$


since area of a square is just a*b and a=b
area equals a*a or a^2 so divide the two out
$$a^2=\frac{225}{2}$$

 

[Tom McCurdy]

I believe 22 is wrong
23 is right rounded
24 is right rounded

 

[Tom McCurdy]

22. by law of sines

$$\frac {73}{\sin{\theta}}=\frac{x}{\sin{\theta}}$$

therefore must also be 73
73*73*.5 = 2664.5