Help what is the slope of the line graphed

Which inequality comparing two of the expressions is true when 0.7 < x < 0.9

Ariana starts with 100 milligrams of a radioactive substance. the amount of the substance decreases by 20% each week for a number of weeks, w. the expression 100(1−0.2)w finds the amount of radioactive substance remaining after w weeks. which statement about this expression is true? a) it is the difference between the initial amount and the percent decrease. b) it is the difference between the initial amount and the decay factor after w weeks. c) it is the initial amount raised to the decay factor after w weeks. d) it is the product of the initial amount and the decay factor after w weeks.

You are riding your bike and notice the square sign above. you mentally draw a straight line from point a to c. describe the angle relationship between dca and bca