Answer:
a) 30cm
b) 20cm
Step-by-step explanation:
a) You've folded the 10 by 10 square in half, so two sides are half its original length (5cm) and the other ones are still 10 cm. So the perimeter is 2(10+5)=30cm
b) Now the 10cm side is folded in half as well so it's 5cm, and the other sides don't change, so the new perimeter is 2(5+5) = 20cm
