1題maths

Substitute (y = 0) into L2,x + 2(0) – 8 = 0x = 8Therefore, the coordinates of C are (8, 0)Area of △ODC : Area of △ABC
= OC² : AC²
= 8² : (8+2)²
= 64 : 100
= 16 : 25Area of △ODC : Area of quadrilateral OABD
= 16 : (25 – 16)
= 16 : 9

If you have any questions, please feel free to ask.
P.S. I have checked that the question comes from 2005 CE Q.13.


2010-09-27 00:01:41 補充：
It is because the two triangles △ODC and △ABC are similar, the ratio of their areas is just the ratio of the squares of the sides of the triangles, i.e. OC² : AC².
If you still have questions, please feel free to ask.

thank you! you are really nice! ^O^
i hope you can always answer my questions!

Subst y=0 into L2,
x=8
C=(8,0)

Area of △ODC : Area of △ABC
=0A² :OC²
=2² : 8²
=4:64
=1:16

Area of △ODC : Area of quadrilateral OABD
=1:(16-1)
=1:15