Classic 12 marbles riddle: Solution Video
 
 
Equation of a circle: CollegeBoard Practice SAT Exam 1_Section 4_Problem 24
 
 
 
Solving a system of equations: CollegeBoard Practice SAT Exam 1_Section 4_Problem 19
 
 
Basic Function Review: CollegeBoard Practice SAT Exam 1_Section 3_Problem 10
 
 
How to find the sum of the interior angles of a polygon