`DeltaABC` में, `angleA:angleB:angleC=2:3:4`, हे| एक रेखा CD, AB के समानांतर खींची गई, तब `angleACD` का मान ज्ञात करे?

Options

A. `40^(@)`
B. `60^(@)`
C. `80^(@)`
D. `20^(@)`

Answer

A

Explanation

According to question,

Given, `angleA+angleB+angleC=180^(@)`
`2+3+4=9` units
`therefore` 9 units =`180^(@)`
1 units = `20^(@)`
`therefore angleA= 2 xx 20^(@)=40^(@)`
`angleB= 3 xx 20^(@)=60^(@)`
`angleC=4 xx 20^(@)=80^(@)`
and AB||CD
`angleB=angleC`
`therefore angleACD = 180^(@)-60^(@)-80^(@)`
`angleACD=40^(@)`