Question

If the area of $△$ on the argand plane, whose vertices are -z,iz,z-iz, is 600 sq. units, then |z| =

• A. 30
• B. 10
• C. 20
• D. 40

Answer 1

The correct option is C

20

z = x + iy

iz = ix + i2y = ix - y

$\therefore$vertices are (-x,-y),(-y,x) and (x+y,y-x)

Area of $△$ = $\left|\frac{1}{2}\right[3(-x^2-y^2)\left]\right|$ = 600

$\Rightarrow$ $x^2+y^2$ = 400 or $\sqrt{x^2+y^2}$ = 20