Question 8 , Question 9

Dear student,
8)

Given : E and F are mid points of 2 chords AB and CD respectively.

Line EF passes through centre.

To prove : AB//CD

Proof:

∠ O F C = ∠ O E A = 90 ° a s l i n e d r a w n t h r o u g h t h e c e n t r e t o b i s e c t t h e c h o r d i s ⊥ t o c h o r d c o n s i d e r i n g E F a s t r a v e r s a l f o r l i n e s A B a n d C D a s a l t e r n a t e i n t e r i o r a n g l e s o n s a m e s i d e a r e e q u a l s o A B / / C D

Please ask other questions separately
Regards