From point D, the angle of elevation of a cliff top (F) is 42 degrees. After walking 85m along a street inclined at 11 degrees (D to E),the angle of elevation from point E is 55 degrees. a)Work out angles DEF and DFE
b)Find the height of the cliff, FG

well

44-3-3-3=35

35+4+4+4+4=51

so the ansewr would be 51 degreesat 7: 00

it is given that, b ≅ bc and ad ≅ cd  

we need bd perpendicular to ac, then only we can say   triangles axb and cxb are congruent using the hl theorem.

if bd perpendicular to ac, means that ab and cb are the hypotenuse of triangles axb and cxb respectively.

from the given information abcd is a square

if bd and ac bisect each other then ax = cx

then only we can   immediately possible to prove that triangles axd and cxd are congruent by sss congruence theorem.