MATHS(1) [復制鏈接]

In the figure, two circles with centres O and O' touch externally at P. ABC and ADE are common tangents to the circles where B, C, D and E are the points of contact. If the radii of the circles are 8 cm and 6 cm, find

a) the length of DE
b) the length of AD




兩點圓心為O & O'

find x first (x=42 cm)

after finding x, others using pyth theorem, answers are straightforward

how do i find X

Why is X 42?

下面是引用hk20020062於2006-01-29 22:16發表的:
how do i find X
Why is X 42?

similiar triangles

OD:O'E=6:8=2:3

x=14X3???

OD: O'E= AO : AO'

So ....

x= 42