To find the measure of angle \( D \), we need to first identify the relationship between the angles \( A \) and \( D \). Given that \( m∠A = (4x - 10)° \) and \( m∠D = (2x + 22)° \), we look to see if they are related in a way that can help us set up an equation.
Since angles \( A \) and \( D \) are formed by intersecting lines, they are supplementary angles (their measures add up to 180 degrees). Therefore, we can write the equation:
\[ m∠A + m∠D = 180° \]
Substituting the expressions for angles \( A \) and \( D \):
\[ (4x - 10) + (2x + 22) = 180 \]
Now, we will combine like terms:
\[ 6x + 12 = 180 \]
Next, subtract 12 from both sides:
\[ 6x = 168 \]
Now, divide by 6:
\[ x = 28 \]
With the value of \( x \) found, we can now find \( m∠D \):
\[ m∠D = 2x + 22 \]
Substituting \( x = 28 \):
\[ m∠D = 2(28) + 22 = 56 + 22 = 78 \]
Therefore, the measure of \( ∠D \) is
\[ \boxed{78°} \]