00:01
In this problem, they're asking us to find the value of cos theta, where theta is the angle given in the triangle, and this particular angle is 90 degrees as given.
00:10
Let's first of all name this triangle.
00:11
I'm going to name this as a, b, and c, so it's easier to represent.
00:18
From the pythagoras theorem, we know that bc can be approximated as square root of, not approximated, according to the theorem, it is bc equal to 13 squared, rather it should be perfectly ab squared plus ac squared, ab squared minus ac squared, because ab is the hypotenuse in this case.
00:53
Therefore, the square root of 13 squared minus 12 squared equals to 5.
01:02
So cos theta is nothing but the adjacent side divided by the hypotenuse, hyb...