Q:

Perimeter of a rectangle with four circles in each corner

my teacher asked a question in exercise for calculate the perimeter of following:

I get result of $144\pi$ and some of my friends got $208.2$ as result (assuming $\pi\approx3.14$).
Q: what's the correct answer of this question ?
I get $144\pi$ with this:
Since each part of circles "not used" is 90° then the rest is 270° (360°-90°)
$360° \rightarrow 2\pi r$
$270° \rightarrow x$
So,
$360x = 270 \times 2\pi 5$
$x = \frac{2700\pi}{360}$
$x = 7,5\pi$
$P = (2\times45) + (2\times12) + (4\times7,5\pi) = 144\pi$

A:

You're reasoning is just fine, until the last line: 
Only one term in the sum has a factor of $\pi$, so the correct answer should be $$\begin{align} P & = 2\cdot 12 + 2\cdot 45 + 4\cdot 7.5\pi \\ \\ & = 24 + 90 + 30 \pi \\ \\ & = 114 + 30\pi \approx 208.2\end{align}$$

