definition of rectangle

Rectangle
This time, I would to tell you about “Rectangle”
The definition of a rectangle is quadrilateral that has four right angle, in other word the value of each angle is 90 degree.
For example : rectangle of ABCD, there are four sides : AB-BC-CD-AD
Side AB and side DC is parallel, side AC and side BD is parallel.
Side AD adnd side BC are diagonal a rectangle. Side AD is 12 cm long, side CD is 8 cm long. Determine long of side AC !
Solution :
We will determine long of side AC.
To find long of side AC we use the Pythagoras theorem because angle of ACD is a right angle.
AD^2 = AC^2 + CD^2
12^2 = AC^2 + 8^2
AC^2 = 144 – 64
= 80
AC = root of 80
= 8,94
So, long of side AC is 8,94 cm.
That’s about rectangle.
I think is enough. Thank you for your attention.