Answer: c
Step-by-step explanation:
Answer: She should budget $672.89 monthly next year for this service.
Step-by-step explanation:
Since we have given that
Amount he was able to save per month = $48.50
Total amount he spent for the year = $1254.89
Amount he saved for the year would be

Amount left from total would be

Hence, She should budget $672.89 monthly next year for this service.
The exact value for cos(pi/16) would be :
cos (pi/16) = +/- √1+cosa/2
cos (pi/4) = sqrt2/2
Hope this helps