बिंदु I , `DeltaABC` का अन्तः केंद्र हे तथा `angleB=70^(@)` तथा `angleC=50^(@)` हे| तब `angleBIC` का मान ज्ञात करे?

Options

A. `130^(@)`
B. `60^(@)`
C. `120^(@)`
D. `105^(@)`

Answer

C

Explanation

According to question,

As we know that
`angleA+angleB+angleC=180^(@)`
`therefore angleA=180^(@)-70^(@)-50^(@)`
`angleA=60^(@)`
`therefore angleBIC=90^(@)+1/2xx60^(@)`
`angleBIC=120^(@)`