Answer:
Measure of angle M = 41°
Explanation:
From the figure attached,
NM ≅ NO [Given]
Therefore, ∠O ≅ ∠M [Opposite angle of the equal sides]
By triangle sum theorem,
m∠O + m∠N + m∠M = 180°
m∠O + m∠N + m∠O = 180° [Since, ∠M ≅ ∠O]
By substituting the values of the given angles,
(4y - 15)° + (7y)° + (4y - 15)° = 180°
(15y - 30) = 180
15y = 210
y = 14
Therefore, m∠M = (4y - 15)°
= 4(14) - 15
= 56 - 15
= 41°