The point halfway between two end points is called a midpoint
Answer:
875
Step-by-step explanation:
30*15=450
30*10=300
20*5=100
12.5+12.5=25
450+300+100+25=875
I worked from bottom to top
Answer:
9
Step-by-step explanation:
perfect square sholud be 
so (w+3)*(w+3) is perfect square and extention of it is =>w*w+6w+9