Fred is safety conscious. he knows that to be safe, the distance between the foot of the ladder and the wall should be 1/4 the height of the wall, fred needs to get on the roof of the school building which is 20 ft tall. how long should the ladder be if he wants it to rest on the edge of the roof and meet safety standards? round your answer to the nearest tenth.

The height of a triangle is 4 in. greater than twice its base. the area of the triangle is no more than 168 in.^2. which inequalitycan be used to find the possible lengths, x, of the base of the triangle?

Can someone me with #s 8, 9, and 11. with just one of the three also works. prove using only trig identities.

In a test for esp (extrasensory perception), a subject is told that cards only the experimenter can see contain either a star, a circle, a wave, or a square. as the experimenter looks at each of 20 cards in turn, the subject names the shape on the card. a subject who is just guessing has probability 0.25 of guessing correctly on each card. a. the count of correct guesses in 20 cards has a binomial distribution. what are n and p? b. what is the mean number of correct guesses in 20 cards for subjects who are just guessing? c. what is the probability of exactly 5 correct guesses in 20 cards if a subject is just guessing?