Well this is an equilateral triangle so then a=b. so then b=4 as well. so then now you have a^2 + b^2=c^2.
4^2+4^2=c^2
16+16=c^2
32=c^2
Find the square root of 32 which is approximately 5.65685.
Find the square root of c^2 which is c.
so then 5.65685=c
