Question

given
$m\angle sqt = 180^{\circ}$
definition of a straight angle
$m\angle sqv+m\angle vqt=m\angle sqt$
angle - addition postulate
$m\angle sqv + m\angle vqt=180^{\circ}$
substitution property of equality
given
$m\angle vqt+m\angle zrs = 180^{\circ}$
reason a
$m\angle sqv+m\angle vqt=m\angle vqt+m\angle zrs$
reason b
$m\angle sqv+m\angle vqt - m\angle vqt=m\angle vqt+m\angle zrs - m\angle vqt$
$m\angle sqv=m\angle zrs$
reason c
$\angle sqv\cong\angle zrs$
definition of congruence
which property of equality accurately completes reason c?
addition property of equality
division property of equality
substitution property of equality
subtraction property of equality

Explanation:

The step from $m\angle SQV + m\angle VQT - m\angle VQT=m\angle VQT + m\angle ZRS - m\angle VQT$ to $m\angle SQV = m\angle ZRS$ is based on the Subtraction Property of Equality. This property states that if you subtract the same quantity from both sides of an equation, the equality still holds. Here, $m\angle VQT$ is subtracted from both sides of the equation.

Answer:

Subtraction Property of Equality