Question

The picture shows a portion of an irrigation system for a farm. BC is the main water pipe.
What is the length of the water pipe AB?

10.4 feet

16.3 feet


9.4 feet

13.3 feet

Answer 1

Do you know what special triangles are?

Answer 2

do you know trigonometry, or do you know "special right triangles"
special right triangles are 30-60-90 and 45-45-90

Answer 3

i know the special triangles a little bit :)

Answer 4

video on 45-45-90 triangles
http://www.khanacademy.org/math/geometry/triangles/v/45-45-90-triangles

Answer 5

Oh, these questions are easier to answer if you know special triangles a lot more than a little bit!

the idea is the legs of a 45-45-90 triangle are equal to each other, and are equal to the hypotenuse divided by sqrt(2)

Answer 6

i know them I just confuse them I know the sides are equal and i want to say the 45-45-90 triangle has the sqrt of 2 and the sides of it are x cause the 60-30-90 has the sqrt of 3 and one side is 2x and the other is x

Answer 7

one way to remember 45-45-90. draw a right triangle with 2 legs = 1
the hypotenuse (using pythagoras) is 1^2+1^2= h^2 so
h^2 = 2
and h= sqrt(2)
the hypotenuse is sqrt(2) times bigger than the legs.
the legs are 1/sqrt(2) bigger (that is, smaller) than the hypotenuse

Answer 8

but, can you answer the question?

Answer 9

i got 9.4 when I did it in my calculater I am not sure If i plugged it in right

Answer 10

is BC a leg or the hypotenuse?

Answer 11

I want to say it is the leg

Answer 12

wouldnt where the question mark is be the hypotenuse?

Answer 13

the hypotenuse is opposite the right angle.