ABCD is a parallelogram - Edexcel - GCSE Maths - Question 3 - 2017 - Paper 1

Since ABCD is a parallelogram, the opposite angles are equal. Therefore, angle DAB (which is equivalent to angle ABC) is equal to angle DCB, which is 75°.

Angle EFD is given as 35°. Therefore, to find angle ABF, we can use the fact that angles on a straight line sum to 180°:

$180° - 35° = 145°$

Now we know that angle DAB = 75°, and using the straight line relationship:

$ABF + DAB = 145°$

Substituting the known value:

$ABF + 75° = 145°$

Thus, we can solve for angle ABF:

$ABF = 145° - 75° = 70°$

Therefore, we have shown that angle ABF = 70°.