What is 3.405 written in expanded form

Asand dune stands 5 feet’s above sea level. the hill is eroding at a rate of 1 foot per 20 years. let y represent the height of the sand dune after x years which equation represents the situation

Add the two expressions 3.8b - 7 and 2.9b + 9 enter your answer in simplified form

The circumference of a redwood tree trunk is 20π ft, and it is 100 ft tall. what is the approximate volume of the redwood tree trunk? 1,000π ft3 10,000π ft3 4,000π ft3 40,000π ft3