The square ABCD has side length 20cm.
E is the midpoint.

22.4 cm

Step-by-step explanation:

AB = 20 cm, BE = (1/2) * 20 cm = 10 cm

By pythagorous theorem,

AE = cm = cm = 22.4 cm

The length of AE is 22.36 cm

Step-by-step explanation:

Given,

In the fig: AB = 20 cm

E is the mid point of BC.

So, BE = 10 cm

To find the length of AD

Here,

ΔABE is a right angle triangle.

So,

Now, putting the values of AB and BE we get,

or, = 400+100

or, AE = = 10

= 10×2.236 = 22.36 (approx)

where is the picture

step-by-step explanation: