oil is leaking out of a tank. the depth of oil in the tank for 60 seconds is shown below. use the graph to work out the rate of decrease of depth, in cm/s, at 10 seconds. you must show your working.

Step-by-step explanation:

draw a tangent starting from (0,80) and touches at (10,60)... Example attached if needed... Good Luck! ;)

60.96438

step-by-step explanation:

last option

step-by-step explanation:

given that δdef is right and isoceles,

assuming that side df is the hypotenuse means that de an ef are the other 2 sides that intersect at 90° and are of equal length.

because they are of equal length, we can say that they are congruent

because they intersect at 90°, their slopes must be opposite reciprocals.

only the last option satisfies these conditions.