In a triangle ABC, if sin A sin B=abc2, then the triangle is
equilateral
isosceles
right angled
obtuse angled
Given, sin A sin B=abc2⇒c2=absin A sin B=(asin A)(bsin b)⇒c2=(csin C)2 ∵(asin A=bsin B=csin C=)⇒sin2C=1⇒C=900Hence,ΔABCis a right angled triangle.
If for a △ABC,cotA. cotB. cotC>0 then the triangle is
The anlges of a triangle are in ratio 3 : 5 : 7. The triangle is
(a) Acute angled
(b) Obtuse angled
(c) Right angled
(d) An isosceles triangle