The value of m∠1 = 68°
Remember that the sum of the interior angles in any triangle must be equal to 180 degrees
In the triangle SAB
m∠ASB+m∠SAB+m∠SBA = 180°
Find the measure of angle ASB
we know that
m∠ASB + 115° = 180° ----> by supplementary angles (form a linear pair)
m∠ASB = 180° - 115° = 65°
Find the measure of angle SBA
we know that
m∠SBC = 133º ----> by corresponding angles
Remember that
m∠SBA+m∠SBC = 180° ---> by supplementary angles (form a linear pair)
substitute
m∠SBA+133° = 180°
m∠SBA 180°-133° = 47°
Find the measure of angle SAB
m∠ASB+m∠SAB+m/SBA = 180°
substitute
65°+m∠SAB +47° = 180°
m∠SAB 180° - 112° = 68°
Find the measure of angle 1
we know that m1 = m/SAB ----> by vertical angles
therefore
m∠1 = 68°