Answer:
The area of rectangle =21 sq units .
Step-by-step explanation:
Given the four vertices of rectangle are 1+4i,-2+4i, -2-3i and 1-3i.
Consider ABCD is a rectangle and its vertices are 1+4i,-2+4i,-2-3i and 1-3i.
First we find sides of rectangle
AB=vertices of B- vertices of A
AB= -2+4i-(1+4i)=-3
<h3>If complex number=a+bi</h3><h3>Then modulus=

</h3><h3>Length of AB=

=3 ( Because magnitude = length always positive ) </h3>
BC= Vertices of C - vertices of B
BC=-2-3i-(-2+4i)=-7i
Length of BC=
=7 ( Magnitude always positive)
CD= vertices of D- vertices of C
CD= 1-3i-(-2-3i)=3
Length of CD=
=3 ( Magnitude always positive)
DA= vertices of A - vertices of D
DA= 1+4i-(1-3i) =7i
Length of DA=
=7 ( Magnitude always positive)
AB=CD and DA= BC
Length BC=7 units
Breadth AB=3 units
Area of the rectangle = 
Area of rectangle =
<h3>Area of rectangle=

=21 sq units .</h3>