Answer:
Use pythagorean theorem. 
Explanation:
The length of the shorter sides are 1 & 4
1^2+4^2=c^2
1+16=c^2
17=c^2 
So, the length, rounded to the nearest whole inch, would be 4.
To find the perimeter, you need to find the side lengths first. 
The short sides are 6 & 7. 
6^2+7^2=c^2
36+49=c^2
85=c^2
So the length for that would be 8, in the nearest whole number.
Add all of the side lengths together. 
6+7+8= 21
The perimeter is 21.