Find value of (0.001) 1/3

Plz. yesterday, the snow was 2 feet deep in front of archie’s house. today, the snow depth dropped to 1.6 feet because the day is so warm. what is the percent change in the depth of the snow?

Geometry in the diagram, ∠abc is a right angle. ∠dbc = 30°27'40". find the measure of ∠abd.

Mat bought a phone for $100. he has to pay $30 per mouth. if he has paid $640 in total, how many mouth has he had the phone?