find slope-intercept form; number of combos; series sum; etc

[heybeautiful009]

14. find slope intercept form of the equation of the line passing through the point (8,1) and is perpendicular to y=4x-3

15. the radar for a county airport control tower is located (3,4) on the map. it can detect a plane up to 15 milies away..write an equation for outsid limits that a plane can be detected.

16. a ladder 15ft long rests against the wall of a house. the foot of the ladder is on level ground 4ft from the wall. to the nearest hundreth what is the measurement of the angle formed between the ladder and the ground?

19. there are different 5 soups, 4 sandwiches and 3 fruits. how many lunch possibliities are there if each meal consists of one of each?

20. find the sum of the arithmetic series a=8 d=4 n=30

21. find A in triangle ABC if a=50 degrees b=14 and c=9

please reply and help me! its be greatly appreciated

 

[Loren]

Re: some math help from my final

>find slope intercept form of the equation of the line passing through the point (8,1) and is perpendicular to y=4x-3

You can start by using the point-slope form for a line which I'm sure you have memorized by now, and the fact that the slopes of lines perpendicular to each other are negative reciprocals of each other.
\(\displaystyle y-y_1 = m(x-x_1)\)

You can deduce the value of m from your given equation knowing that the slope-intercept form of a line is y=mx+b. (There's m again).

For the second one, I guess if you stand in one place and can see exactly 15 miles in all directions, the limit of your vision would form a circle???


16. a ladder 15ft long rests against the wall of a house. the foot of the ladder is on level ground 4ft from the wall. to the nearest hundreth what is the measurement of the angle formed between the ladder and the ground?
Did you draw a sketch of this? You should have a right triangle, the short leg representing the ground, the long leg representing the side of the house and the hypotenuse representing the ladder. Label the legs according to the information given. Then use the appropriate trigonometric ratio. You will have something like...
\(\displaystyle \cos x = \frac{a number}{another number}\). From that, it should be quite easy to determine x using your knowledge about the definition of arccosine.

 

[Denis]

Re: some math help from my final

please reply and help me! its be greatly appreciated

How can we help if we don't know where you're stuck?