किसी `DeltaABC` में, `AB^(2)+AC^(2)=BC^(2)` तथा `bar(BC)` है| तब `angleABC` है?

Options

A. `30^(@)`
B. `45^(@)`
C. `60^(@)`
D. `90^(@)`

Answer

B

Explanation

Accoriding to question,
ABC is a right angle triangle
`therefore` By using pythagoras theorem

`BC^(2) = AC^(2)+AB^(2)` and BC=`sqrt(2)AB` (given)
Now,
`(sqrt(2)AB)^(2) = AC^(2)+AB^(2)`
`2AB^(2) = AC^(2)+AB^(2)`
`AC^(2) = AB^(2)`
AC=AB
`therefore angleABC=angleACB=45^(@)`
Equal side have equal angle