Find the area of a rectangle of length 4cm and whose diag...
Find the area of a rectangle of length 4cm and whose diagonal is 8cm, (Leave your answer in surd form)
A.
8√3cm2
B.
12√3cm2
C.
16√2cm2
D.
16√3cm2
Correct answer is D
|AB| = 4cm
|BC| = 8cm
In right-angled BAC;
82 = 42 + |AC|2
|AC|2 = 82 - 42
|AC\2 = 64 - 16 → 48
|AC| = √48cm → 4√3cm
The area of rectangle = L x B
= |AB| x |AC|
= (4×4√3cm2
=16√3cm2