Question

show that SQ +SR < PQ +PR

Answer 1

look at the following picture

Answer 2

Here the angle opposite side of PR is angQ
the angle opposite side PQ is angR


the angle opposite to side SQ is angSRQ
the angle opposite to side SR is angSQR

Now angle SQR<Q
angle SRQ<R

So, if the side opposite to greater angle so side is greater


hence, proved that SQ+SR<PQ+PR