Ratio of inradius to circumradius in triangle

If two sides of a triangle are roots of the equation x^(2) -7x + 8 = 0 and the angle between these sides is 60^(@) then the product of inradius and circumradius of the triangle is

If two sides of a triangle are roots of the equation x^(2)- 7x + 8 = 0 and the angle between these sides is 60^(@) then the product of inradius and circumradius of the triangle is

If two sides of a triangle are roots of the equation x^(2) -7x + 8 = 0 and the angle between these sides is 60^(@) then the product of inradius and circumradius of the triangle is

In a triangle ABC, angleC=90^@, r and R are the inradius and circumradius of the triangle ABC respectively, then 2(r+R) is equal to

ABC is an isosceles triangle in which AB = AC and (angleA)= 2(angleB) AB = 4 cm . What is the ratio of inradius to the circumradius?