Question

1. if m∠abc is one degree less than three times m∠abd and m∠dbc = 47°, find each measure.

Explanation:

Step1: Set up an equation

Let $m\angle ABD = x$. Then $m\angle ABC=3x - 1$. Since $\angle ABC=\angle ABD+\angle DBC$ and $\angle DBC = 47^{\circ}$, we have the equation $3x - 1=x + 47$.

Step2: Solve the equation for x

Subtract $x$ from both sides: $3x-x-1=x - x+47$, which simplifies to $2x-1 = 47$. Then add 1 to both sides: $2x-1 + 1=47 + 1$, so $2x=48$. Divide both sides by 2: $x=\frac{48}{2}=24$.

Step3: Find $m\angle ABD$ and $m\angle ABC$

$m\angle ABD=x = 24^{\circ}$. $m\angle ABC=3x - 1=3\times24-1=72 - 1=71^{\circ}$.

Answer:

$m\angle ABD = 24^{\circ}$, $m\angle ABC=71^{\circ}$