Question

exterior angle measure
m∠dca = m∠a + m∠b
m∠dca =
+
m∠dca =

Explanation:

Step1: Identify angle values

$m\angle A = 59^{\circ}$, $m\angle B=40^{\circ}$

Step2: Apply exterior - angle formula

$m\angle DCA=m\angle A + m\angle B$
$m\angle DCA=59^{\circ}+ 40^{\circ}$

Step3: Calculate the result

$m\angle DCA = 99^{\circ}$

Answer:

$99^{\circ}$