Question

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

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

Answer 1

The correct option is C an acute angled triangle

Let the proportional quantity be x
so, $5x+3x+7x={180}^{\circ }$
$15x={180}^{\circ }$
$x={12}^{\circ }$
So, angle of triangles are:
${12}^{\circ }\times 5={60}^{\circ }$
${12}^{\circ }\times 7={84}^{\circ }$
${12}^{\circ }\times 3={36}^{\circ }$
Since, all the angles are less than ${90}^{\circ }$, the given triangle is acute angled triangle.