If `A B C` and DEF are two triangles such that ` A B C\ ~= F D E\ a n d\ A B=5c m ,\ /_B=40^0\ a n d\ /_A=80^0dot` Then, which of the following is true? `D F=5c m ,\ /_F=60^0` (b) `D E=5c m ,\ /_E=60^0` `D F=5\ c m ,\ /_E=60^0` (d) `D E=5c m ,\ /_D=40^0`

Explanation

Given: `triangleABC~=triangleFDE`
`AB=5cm` , `angleA=80^@`and `angleB=40^@`
Solution:In`triangleABC`
`angleA+angleB+angleC=180^@` ( By angle sum property of a triangle )
`80^@`+`40^@`+`angleC`=`180^@`
`angleC`=`180^@`-`120^@`
`angleC`=`60^@`
`therefore` By CPCT
`AB=DE=5cm`
`angleC`=`angleE`=`60^@`
Hence,option (b) is correct.