Please could you answer my question

CDEF is a trapezium

ABCF is a rectangle and perimeter is20cm
BD=9cm
AB=6cm
EF=3cm
What is the area of CDEF

Sure, you have to ask the question first though

tell us da answer

nope

Of course! I'm here to help. What is your question?

Okay so we know the perimeter is 20cm, that means using the rectangle formula for perimeter

Perimeter =2(Length +Width)

Substitute the numbers we have

20cm=2(6cm+Width)
20cm=12cm+2Width
4=Width (after rearranging it)

So we have found the answer for BC which is 4cm which makes CD 5 cm

At this point you use the Trapezium area formula