How to do question 5,6,7,8

Dear student, 
Answer for Q8 is provided below. 
For further questions, repost in separate threads for rapid assistant. 
First we will have to draw a line PQ of 5 cm 
stretch your compass 5cm
keep it on point P
draw a line of 5cm which is 90 degree of Line PQ and name new point as S
now put the compass of 5 cm on  Q and drow 90° to get R
now joint R and S
you find a square of 5 ×5 cm

Regards.