Can someone explain the basics of trignometry for class 10th. And the 3 formulas there in NCERT Class 10th Maths(India)
I am class 9th student and want to know the trignometry in advance.

Scores on a university exam are normally distributed with a mean of 78 and a standard deviation of 8. the professor teaching the class declares that a score of 70 or higher is required for a grade of at least “c.” using the 68-95-99.7 rule, what percentage of students failed to earn a grade of at least “c”?

3/4 = c/36 i need with this fraction proble.

What is 5 kilometers turned into meters