15. [I2 Paints] SALGTRlGd 4.5.093.M|. PRACTICE ANOTHER Environmental scientists measure the intensity or light at various depths in a lake to nd the \"transparency\" of the water. Certain levels mf transparency are required for the biodiversity of the submerged macrnphyte population In a certain lake the intensity or light at depth xis given by I = 8970.11le where I is measured in lumens and x in feet. (a) Find the intensity rat a depth or45 R. [Round your answer to two decimal places.) lumens (b) At what depth has the light intensity dropped to r : 4? (Round your summer ta one decimal place.) \\:|ft Need Help