This problem can be directly calculated by the coefficient of sinking fund, or by the reciprocal of the final coefficient of ordinary annuity.

Calculation of annual sinking fund (known final value F, find annuity A)

A = F * I/[( 1+I)n- 1]= F *(A/F，I，n)

= 200 *10%/[(1+10%) 4-1] (note that 4 here refers to the fourth power).

=20/( 1.464 1- 1)

=43.094 16074

I/[( 1+i) n-1] is the sinking fund coefficient, which is recorded as (A/F, I, n).