A right angle measures 90 degrees and is the intersection of two perpendicular lines. In diagrams, a right angle is indicated by a small box completing a square with the perpendicular lines.

Angles around a line add up to 180°. Angles around a point add up to 360°. When two lines intersect, adjacent angles are supplementary (they add up to 180°) and angles across from either other are vertical (they're equal).

To multiply monomials, multiply the coefficients (the numbers that come before the variables) of each term, add the exponents of like variables, and multiply the different variables together.

(4a)(6ab) + (4a²)(4b)
(4 x 6)(a x a x b) + (4 x 4)(a² x b)
(24)(a¹⁺¹ x b) + (16)(a²b)
24a²b + 16a²b
40a²b

To solve this equation, replace the variables with the values given and then solve the now variable-free equation. (Remember order of operations, PEMDAS, Parentheses, Exponents, Multiplication/Division, Addition/Subtraction.)

2a(a - z)
2(2)(2 + 8)
2(2)(10)
(4)(10)
40

To multiply monomials, multiply the coefficients (the numbers that come before the variables) of each term, add the exponents of like variables, and multiply the different variables together.

9a x 6b = (9 x 6) (a x b) = 54ab