I learned how to use elimination and substitution.

Now I can two methods to solve questions.

2

To be continue …

Question 1. I find the X is opposite and 6 is adjacent. So I should use tangent in this question. Then, just like you see, I got the answer (>~<) .

Question2. In this question, the X is the angle which we should found. The 16 is hypotenuse and the 12 is adjacent. So we should use Cos to solve this question. 12 over 16 is equal to 3over 4, then we moved X degree to the left side and moved others to the right side.

Question3. In this question, the X is hypotenuse( what a piquant X…) and 50 degree is the angle we worked with, 8 is the opposite. Now we got hypotenuse and opposite, so we can use Sin. In the right side of equal mark is 8/x, we should let both side to time X. Then X was moved to the left side. We should move sin50 degree to the right side, then the right side has 8/sin50 degree. Now we can figure out the answer.

In this week, I figured out an important question:

Now we know that in this cuboid, Height equals c, Width equals b, and Length equals a. We should give a equation to express d.

How to figure out the equation?

First, add a new line. We named it “e”

Second, use the Pythagorean theorem.so

Because a^2 + b^2= c^2

So e^2=a^2+b^2, and d^2=c^2+e^2

So d^2=a^2 + b^2 + c^2

at last, use radical sing to calculate a precise number of d.