I count five 'k's there, so that part of the expression is
k⁵ .
Two 'n's form the rest of it, so that part is n² .
The parts are multiplied, so the simplest form of the expression is
k⁵ n² .
to calculate pi you can use the Nilakantha Series.
Sinx=1/2
sin30=1/2
therefore x=30 degree
The number is assumed to be x
x of 40% = 56
x * (40/100) = 56
x = 5600 / 40
x = 140
Changing the subject of an equation involves solving for another variable in the equation
The equation of t is 
<h3>How to change the subject of the equation</h3>
The equation is given as:
![N=\sqrt[2]{\frac{y_i-y_o}{t^2}}](https://tex.z-dn.net/?f=N%3D%5Csqrt%5B2%5D%7B%5Cfrac%7By_i-y_o%7D%7Bt%5E2%7D%7D)
Rewrite the equation as:

Evaluate the square root of t^2

Multiply both sides by t

Make t the subject, in the above equation

Hence, the equation of t is 
Read more about subject of formula at:
brainly.com/question/657646