User:
• Matrices
• Algebra
• Geometry
• Funciones
• Trigonometry
• Coordinate geometry
• Combinatorics
 Suma y resta Producto por escalar Producto Inversa
 Monomials Polynomials Special products Equations Quadratic equations Radical expressions Systems of equations Sequences and series Inner product Exponential equations Matrices Determinants Inverse of a matrix Logarithmic equations Systems of 3 variables equations
 2-D Shapes Areas Pythagorean Theorem Distances
 Graphs Definition of slope Positive or negative slope Determine slope of a line Ecuación de una recta Equation of a line (from graph) Quadratic function Posición relativa de dos rectas Asymptotes Limits Distancias Continuity and discontinuities
 Sine Cosine Tangent Cosecant Secant Cotangent Trigonometric identities Law of cosines Law of sines
 Ecuación de una recta Posición relativa de dos rectas Distancias Angles in space Inner product

# Find measures of complementary, supplementary, vertical, and adjacent angles

$\angle\;A$ and $\angle\;B$ are complementary angles. If $\angle\;A=50^o$, find the measure of $\angle\;B$.

Because $\angle\;A$ and $\angle\;B$ are complementary angles, $\angle\;A\;+\;\angle\;B=90^o$. Substituting 50º for $\angle\;A$ gives

$50^o\;+\;\angle\;B=90^o$.

Subtracting 50º from both sides, we find that $\;\angle\;B=90^o-50^o=40^o$.

$\angle\;A$ and $\angle\;B$ are supplementary angles. If $\angle\;A=125^o$, find the measure of $\angle\;B$.

Because $\angle\;A$ and $\angle\;B$ are supplementary angles, $\angle\;A\;+\;\angle\;B=180^o$. Substituting 125º for $\angle\;A$ gives

$125^o\;+\;\angle\;B=180^o$.

Subtracting 125º from both sides, we find that $\;\angle\;B=180^o-125^o=55^o$.

Determine the measures of $\angle\;2,\;\angle\;3,\;and\;\angle\;4$

Because vertical angles are equal, $\angle\;4=120^o$.

Because adjacent angles add up to 180º, then $\angle\;3\;+\;\angle\;4=180^o$. We also know $\angle\;4=120^o$. Substituting gives

$\angle\;3\;+\;120^o=180^o$.

Subtracting 120º from both sides, we find $\angle\;3=60^o$.

Because $\angle\;3$ and $\angle\;4$ are vertical, they must be equal. Therefore $\angle\;2=60^o$.