Final answer:
The sum of the three angle measures in a triangle is always 180°.
Step-by-step explanation:
In Δklm, m∠k = 24° and m∠l = 135°. To determine which statement about the sides of Δklm must be true, we can analyze the given angle measures.
Since the sum of the angles in a triangle is always 180°, we can calculate the measure of angle m∠m by subtracting the measures of angles m∠k and m∠l from 180°:
m∠m = 180° - m∠k - m∠l = 180° - 24° - 135° = 21°
Based on the values obtained, it can be concluded that the statement 'The sum of the three angle measures in Δklm is 180°' must be true.