Question

The angles of a triangle are in the ratio 5:3:7. The triangle is:

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

Answer 1

The correct option is A an acute angled triangle

The angles of the triangle are in the ratio: $5:3:7$
Let the angles be $5x,3x,7x$
By Angle sum property,
$5x+3x+7x=180$
$15x=180$
$x=12$
Thus, angles are, ${60}^{\circ },{36}^{\circ },{84}^{\circ }$
Since, all the angles are less than ${90}^{\circ }$, it is an acute angled triangle.