Atriangle has side lengths 4, 7 and 9. what is the measure of the angle across from the longest side? 92 = 42 + 72 − 2g4g7cos(a) 81 = 16 + 49 − 56cos(a) 81 = 9cos(a) 9 = cos(a) a cannot exist! gabe tried to use the law of cosines to find an unknown angle measure in a triangle. his work is shown. what is gabe’s error? gabe reversed the order of the 9 and the 4. gabe squared the numbers incorrectly. gabe should not have subtracted 56 from 16 + 49. gabe incorrectly stated that cos–1(9) is not defined.

Stephen thublin invests $1,000,000 in a 45-day certificate of deposit with 6.55% interest. what is the total interest income from the investment?

Julie buys 2kg of apples and 7kg of pears ? 12.70. the pears cost ? 1.30 per kilogram what is the price per kilogram of the apples? show your working out

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.