Two lines are respectively perpendicular to two parallel lines. Show that they are parallel to each other.
A triangle ABC is right angled at A. L is a point on BC such that AL ⊥ BC. Prove that ∠ BAL = ∠ ACB.
The angles of a triangle are in the ratio 2 : 3 : 4. Find the angles of the triangle.
Two lines l and m are perpendicular to the same line n. Are l and m perpendicular to each other? Give reason for your answer.
If one of the angles formed by two intersecting lines is a right angle, what can you say about the other three angles? Give reason for your answer.
Two adjacent angles are equal. Is it necessary that each of these angles will be a right angle? Justify your answer.
How many triangles can be drawn having its angles as 53°, 64° and 63°? Give reason for your answer.
How many triangles can be drawn having its angles as 45°, 64° and 72°? Give reason for your answer.