Part (a)
Step-by-step Explanation:
As ∠K is a right angle.
i.e.
also
<u>Equation to find x</u>
As we know that The angle sum of a Triangle is 180°.
so
m∠K + m∠L + m∠M = 180°






Part (b)
Step-by-step Explanation:
Finding the degree measures of each angle.
As
As ∠K is a right angle.
so
Putting
in m∠L = (2x+19)°
m∠L = (2x+19)°
= 


so
m∠L = 39.8°
Putting
in m∠M = (3x+21)°
m∠M = (3x+21)°



so
m∠M = 50.2°
Verification:
m∠K + m∠L + m∠M = 180°
90° + 39.8° + 50.2° = 180°
90° + 90° = 180° ∵ 39.8° + 50.2° = 90°
180° = 180°