If the angles are in the ratio `5 : 3 : 7,` then the triangle is

Options

A. an acute angled triangle
B. an obtuse angled triangle
C. a right angled triangle
D. an isosceles triangle

Answer

`B`

Explanation

Given, the ratio of angles of a triangle is `5 : 3 : 7`
Let angles of a triangle be `/_A, /_B and /_C.`
Then, `" "/_A = 5X,/_B = 3X and /_C = 7x`
In `Delta ABC, " " /_A + /_B + /_C = 180^(@) ["since, sum of all angles of a triangle is" 180^(@)]`
`:. " " 5x + 3x +7x = 180^(@)`
`rArr " " 15x = 180^(@)`
`rArr " "x = 180^(@)/15 = 12^(@)`
`:. " " /_A =5x = 5xx12^(@) = 60^(@)`
`/_B = 3x = 3xx12^(@) = 36^(@)`
and `" " /_C = 7x = 7xx12^(@) = 84^(@)`
Since, all angles are less then `90^(@)`, hence the triangle is an acute angled triangle .