Two lines and a ray intersect at a point as shown in the diagram
Write and solve an equation to find the value of 2 Find the measure of
DAE
110°
A
D
(+4)
30
E

m<DAE = 80°

Step-by-step explanation:

Given that m<CAB = 110°,

m<DAE = (x + 4)°,

m<EAF = 30°,

m<EAF + m<DAE = m<DAF (angle addition postulate)

30° + (x + 4)° = m<DAF (substitution)

(34 + x)° = m<DAF

<DAF and <CAB are vertically opposite angles. Vertically opposite angles are said to be congruent. Therefore:

m<DAF = m<CAB

(34 + x)° = 110° (substitution)

The equation above can be used to solve for x as follows:

34 + x = 110

x = 110 - 34 (Subtracting 34 from both sides)

x = 76

m<DAE = (x + 4)°

Plug in 76, to replace x

m<DAE = 76 + 4

m<DAE = 80°