Since, $12+13 gt 16$
$:.$ Triangle is possible.
Now, $("longest side")^(2)=(16)^(2)=256$
and sum of squares of other sides $=(12)^(2)+(13)^(2)=144+169=313$
Since $("longest side")^(2) lt$ sum of squares of other sides
$:.$ It is an acute angled triangle.
