Question

Find x in this 45°-45°-90° triangle.

Answer 1

You can use trig for this, think of the info you have, you're given an angle and the magnitude of the "hypotenuse" and want to find the "opposite" side
think about SOHCAHTOA
so Sin- O, H
Cos - A, H
Tan- O, A

Answer 2

How do I put SOHCAHTOA into this?

Answer 3

so you have been given the hypotenuse and want to find the opposite side, so you're using H and O, think of what H and O belong to, sin, cos or tan?

Answer 4

sin

Answer 5

yup, so now try and apply sin, show me how you would set up an equation with sin and the info given

Answer 6

It is very important to know the ratios sin, cos and tangent in general.
However, it is equally important to know the properties of two very special triangles,
1. the isosceles right triangle, and the
2. 30-60-90 triangle.

In my opinion, we should be familiar with the properties of these two triangles to the point that we can recognize them as soon as we see one.
1. The isosceles right triangle

some properties:
- measure of the legs (i.e. not hypotenuse) are equal
- meausre of hypotenuse is sqrt(2)*length of a leg
- conversely, measure of a leg is (sqrt(2)/2) of the hypotenuse.
- obtuse angles are both 45.

2. The 30-60-90 triangle

some properties
- the median through the 90 degree angle divides the triangle into two triangles, one equilateral, and the other isosceles 30-30-120.
- measure of hypotenuse is double that of side.
- measure of the long leg is sqrt(3)x where x is the length of the short leg.