please help. urgent

A sector of a circle is inside a rectangle. The rectangle has the side lengths 25cm and 15cm. This also means that the radius of the sector is 25cm. What would be the area in the rectangle that is outside the sector?

The answer is 185cm^2 but i dont no how to get it. Please help!

 $\begin{array}{rcll} A_{\text{rectangle}} &=& 25\cdot 15 \ cm^2 \\ &=& 375 \ cm^2 \\\\ A_{\text{sector of a circle}} &=& \pi \cdot 25^2 \cdot \frac{\varphi}{360^\circ} \ cm^2 \\ A_{\text{Area in the rectangle and outside sector}} &=& A_{\text{rectangle}} - A_{\text{sector of a circle}}\\ A_{\text{Area in the rectangle and outside sector}} &=& 375 \ cm^2 - \pi \cdot 25^2 \cdot \frac{\varphi}{360^\circ} \ cm^2\\ A_{\text{Area in the rectangle and outside sector}} &=& 375 \ cm^2 - \pi \cdot 625 \cdot \frac{\varphi}{360^\circ} \ cm^2\\\\ \sin{(\frac{\varphi}{2})} &=& \frac{\frac{15}{2}}{25} \\ \sin{(\frac{\varphi}{2})} &=& \frac{7.5}{25} \\ \sin{(\frac{\varphi}{2})} &=& 0.3 \\ \frac{\varphi}{2} &=& \arcsin{(0.3)} \\ \frac{\varphi}{2} &=& 17.4576031237^\circ \\ \varphi &=& 2\cdot 17.4576031237^\circ \\ \varphi &=& 34.9152062474^\circ \\\\ A_{\text{Area in the rectangle and outside sector}} &=& 375 \ cm^2 - \pi \cdot 625 \cdot \frac{34.9152062474^\circ}{360^\circ} \ cm^2\\\\ A_{\text{Area in the rectangle and outside sector}} &=& 375 \ cm^2 - 190.432908760 \ cm^2\\\\ A_{\text{Area in the rectangle and outside sector}} &=& 184.567091240 \ cm^2\\\\ A_{\text{Area in the rectangle and outside sector}} &\approx& 185 \ cm^2\\\\ \end{array}$

Well, You know that the formula is for the area of a rectangle. So, When you do all those steps and such, it kind of makes sense on how that answer came to be.

Did i make any sense to you?

No!. Show me the calculation that arrives at the answer of 185 cm^2, please.

A=πr^2 for a circle

A=wl   For a rectangle, 

Is this making any sense?

So you have all these formulas. You use these to plug in the information from above. Do you not have any notes on this stuff?

It doesn't work!. Because  it is a "sector of a circle is inside a rectangle", and NOT a circle?

Here's a pic of the situation :

The intersection point of the side of the rectangle and the circle at F  =  (sqrt(25^2 -7.5^2), 7.5)

And, by symmetry.....the central angle of the sector is given  by 2* tan^-1(7.5/ sqrt(25^2 -7.5^2)) = about 34.915206247444°

So.....the area  of the rectangle outside the sector  = 375 - pi*(25)^2* [ 34.915206247444 / 360)  = [375 - 190.432] cm^2  ≈ 185 cm^2