Help me this hard it is due to day plz

Brainlest answer can you find the area and circumference of a circle given the radius or diameter? if its yes or no explain why

Acertain population of bacteria demonstrates exponential growth doubles in size every 4 days. how long will it take the population to triple in size?

Eric has challenged himself to walk 24,000 steps in 4 days. if eric walks the same number of steps each day, which function represents the number of steps eric still needs to walk to reach his goal with respect to the number of days since he started his challenge? a. y = 8,000x − 24,000 b. y = -8,000x + 24,000 c. y = 6,000x − 24,000 d. y = -6,000x + 24,000