Let `alt=blt=c` be the lengths of the sides of a triangle. If `a^2+b^2 < c^2,` then prove that triangle is obtuse angled .

Let alt=blt=c be the lengths of the sides of a triangle. If a^2+b^2< c^2, then prove that angle C is obtuse .

In a triangle ABC, 8R^2=a^2+b^2+c^2 prove that the triangle is right angled

In triangle ABC if 2sin^(2)C=2+cos2A+cos2B , then prove that triangle is right angled.

If 8R^(2)=a^(2) +b^(2) +c^(2). then prove that the Delta is right angled.

If the sides of a triangle are 3, 5, and 6, prove that the triangle is obtuse - angled triangle and find the obtuse angle.

If in a Delta A B C ,cos^2A+cos^2B+cos^2C=1, prove that the triangle is right angled.

If the lengths of the sides of a triangle are a - b , a + b and sqrt(3a^(2)+b^(2)),(a,bgt,0) , then the largest angle of the triangle , is

Statement-1: If the lengths of two sides of a triangle are roots of the equation x^(2)-12x+35 =0 and the angle opposite to third side is obtuse, then the square of the length of the third side is greater than 74. Statement- 2: In a !ABC,cosC=(a^(2)+b^(2)-c^(2))/(2ab)

Let a,b,c be the sides of a triangle ABC, a=2c,cos(A-C)+cos B=1. then the value of C is

Using vectors: Prove that if a,b,care the lengths of three sides of a triangle then its area Delta is given by Delta= sqrt(s(s-a)(s-b)(s-c)) where 2s=a+b+c