let the consecutive multiples be 7(n-1) , 7n and 7(n+1)
so 7(n-1)+7n+7(n+1)=777
or 3n=111,
n=37
252,259,266
Answer:
The measure of angle C is 
Step-by-step explanation:
we know that
If AB || DC
then
-----> supplementary angles by consecutive interior angles
and remember that the sum of the interior angles in a trapezoid is equal to 360 degrees

step 1
Find the measure of angle D
substitute the measure of angle A
step 2
Find the measure of angle C

substitute the values

