In `Delta ABC and Delta XYZ , "if " angle A and angle X ` are acute angles such that ` cos A =cos X ` then show that `angle A = angle X `

In any triangle ABC if cosA=sinB-cosC then show that any angle of the triangle is a right angle.

If in a triangle ABC, cos^(2)A + cos^(2)B + cos^(2)C =1 , then show that the triangle is right angled.

Express sec A and cos A in terms of sides of right angle triangle

In the triangle ABC, if cos 3 A + cos 3B+ cos 3C=1 , show that the triangle is obtuse-angled.

If the sides of right angled triangle are in G.P then the cosines of the acute angle of the triangle are-

If the bisector of angle A of triangle ABC makes an angle theta with BC, then sin theta is

In Delta ABC, angle B le angle C. If the interior bisector of angle BAC be AP and AQbotBC. then prove that angle PAQ=(1)/(2)(angle B-angleC)

In Delta XYZ , right angle is at Y,YZ =x, and XZ =2x Then determine angle YXZ and angle YZX.

If A,B,C are the angles of a triangle, show that, (i) sin B cos(C +A) + cos B sin (C +A) = 0