एक चक्रीय समलम्ब चतुर्भुज इस तरह है, की AB ||BC , यदि, `angleABC=70^(@)` , तब `angleBCD` का मान ज्ञात करे?

Options

A. `60^(@)`
B. `70^(@)`
C. `40^(@)`
D. `80^(@)`

Answer

B

Explanation

`therefore angleBAD= 180^(@) - 70^(@)=110^(@)`
sum of interior angles between two parallel line is `180^(@)`
`angleBCD=180^(@)-170^(@)=70^(@)`
Note: In trapezium sum of opposite angles are `180^(@)`