Answer:
20 units square
Step-by-step explanation:
do the Pythagoras theorem
a²=b²+c² ⇒ a=√b²+c²
if b is 4 and c is 2 an a is the unknown
so a=√(4)²+(2)²
a=√20
then get the rule of the area of the square
Area of the square= s²
s=a=√20 (a is the hypotenuse of the triangle and also a side in the square)
so s²=20
Area of the square=20 units square
