Answer
The Amplitude is 5
The Period is $ 8\pi$
See graph below
Work Step by Step
For
$y=a\sin c(x−h) + k$ $y =a \cos c(x−h) + k$,
Amplitude: $|a|$, Period: $\frac{2\pi} {c}$,
Given $y = 5 \cos (0.25 x)$
The Amplitude is $|5|$ = 5
The Period is $\frac{2\pi}{0.25} = 8\pi$
The transformations are as follows
The blue graph represents the graph of $\cos x$
The red graph represents the graph of the given function that is compressed horizontally by a factor of 4 (calculated by $\frac{1}{c}$) and stretched vertically by a factor of 5
See graph below.