Can someone help me out?

so basically

the area of the square; (5cm)^2 = 25cm^5

the area of the triangle; (4cm.5cm)/2 = 10cm^2

which means that r = √25cm^2/10cm^2 = √25/10 cm^2 or √10/25 cm^2

english is not my first language so i do not know what combined means but if u explain a little more i will try to help u

-> ok edit edit;

1cm/5in. = r

5cm => 25in.

z^2= area of a square so

25in.25in= 625 in^2

4cm => 20in.

5cm => 25in.

h.b/2 = area of a triangle so

20in.25in./2 = 250in.^2

250in.^2 + 625in.^2 = 875in.^2

so answer B