Hey there!
1/2 x 4/4 = 4/8
So , ? = 4
It depends on if the interest rate of 6% is nominal or not. The question doesn't specify. Let's assume that is is a nominal rate, compounded monthly.
Start with 100000 = x * a angle 132 at .5% per month
This becomes 100000 = x * (1-1.005^-132)/.005
Which becomes (100000(.005))/(1 - 1.005^-132) = x
So x is the PMT, which is 1036.70.
It 90 degrees because even though the side lengths change the angle measure doesn’t