Find the area and perimeter of a square whose length of diag...
Find the area and perimeter of a square whose length of diagonals is 20√2 cm
A.
800 cm2, 80 cm
B.
400 cm, 80 cm2
C.
80 cm, 800 cm2
D.
400 cm2, 80 cm
Correct answer is D
Using Pythagoras theorem
⇒ (20√2)2=x2+x2
⇒ 800 = 2x2
⇒ 400 = x2
⇒ x = √400 = 20 cm
∴ Area of a square = x2=202=400cm2
∴ Perimeter of a square = 4x = 4 x 20 = 80 cm