The correct answer should be Choice B.
If there are 4 prisms together and touching, there are some hidden areas that don't make it out to the surface. Those areas should not be counted in the overall surface area. They should be subtracted.
The answer is C. 21/50 is 0.42. 7/50 is 0.14. 19/50 is 0.38. 43/50 is 0.86. To convert a fraction to a decimal, you will have to divide the numerator by the denominator.
Hope this helped.

Let's find out the gradient (Slope " m ") of line q ;



Now, since we already know the gradient let's find of the equation of line by using its Slope and one of the points using point slope form of line :


Now, plug in the value of gradient ~

here we can clearly observe that, the Area under the curve can easily be represented as :

Since, all the values of y that lies in the shaded region is smaller than the actual value of y for the corresponding values of x in the equation of line q