Answer:
Based on the definition of an isosceles triangle, the measure of angle L is: 43°
An isosceles triangle has two side lengths that are equal in size, and also the angles opposite the equal sides are congruent.
Given that KL ≅ MK in △KLM, it means △KLM is an isosceles triangle.
If m∠M = 43°, therefore, m∠M = m∠L (equal angles directly opposite KL and MK).
This implies that: m∠M = 43°
In summary, based on the definition of an isosceles triangle, the measure of angle M is: 43°