The measures of the angles of def are in the ratio 2: 4: 4. what are the measures of the angles?

So you can simplify that ratio to 1:2:2
DEF is a triangle (there are 3 vertices and therefore 3 sides).
The measures in a triangle add up to 180 degrees.
So you need 2 angles that are twice 1 angle, so set up an equation.

x + 2x + 2x = 180
5x = 180
x = 36
36 is the measure of the smallest angle, so the two other angles are twice that, which are 72 and 72.

So your angles are 36, 72, 72

10.4 is the answer for you