# Week 7 in Math 10

This week we learned something about Trigonmetry . I think this is a very interesting one unit , it’s about triangle and angle. Most problems can be reduced to calculations on right-angle triangl
es.

so : tanA = sin A/ cos A

And the teacher taught us one way to remember the letters is to sound them out phonetically, which is ‘SOH-CAH-TOA’ ,it’s very easy to memory and it’s interesting too.But these are built on the premise of knowing the degree of a corner, so when there is no degree of foot, you need to use the Pythagorean theorem.But also have to be careful when doing questions, the United States as I like a joke.

Write is written 9.3 square plus 4.8 square, and the actual time to do, but it is subtraction😂,then get a equal to 8.0.

And then think about it is really should not, a square plus b square is equal to the square of c, the largest c is less than b, how to see should be wrong.

And the correct answer is 10.5, is bigger than 4.8 and 9.3 , and this is a really convenient and swift way to check the answer whether it is right.

And when you hook the theorem, and found that the two sides is a number, this time in order to identify yourself to do the right, you can visualize, the two corners are equal to 45 degrees, if not 45 degrees, then unfortunately you do Wrong; but even 45 degrees is also best to re-calculate it again.