Answer:
The measure of angle 1 is 115°
Step-by-step explanation:
we know that
If ∠1 and ∠2 are a linear pair
then
∠1 +∠2 =180° -----> supplementary angles
If ∠2 and ∠3 are vertical angles
then
∠2 =∠3
step 1
Find the value of y
we know that
∠2 =∠3
substitute values
(5+4y)°=(6y-25)°
6y-4y=(5+25)°
2y=(30)°
y=15°
step 2
Find the measure of angle 2
∠2=(5+4y)°
substitute the value of y
∠2=(5+4(15))°
∠2=65°
step 3
Find the measure of angle 1
we know that
∠1 +∠2 =180°
we have
∠2=65°
substitute
∠1 +65°=180°
∠1 =180°-65°=115°