If ∆ABC is right angled at C, ∠A = 45o and BC = 7 units then ∠B and AC will be
∠B = 45o, AC = 7 units
∠B = 60o, AC = 8 units
∠B = 90o, AC = 1 unit
∠B = 30o, AC = 9 units
ΔABC is right angled at A. AB = 60 units, AC = 80 units and BC = 100 units. D is a point between B and C such that ΔADB and ΔADC have equal perimeters. What is the length of BD?
△ ABC, right angled at B, ∠ACB = 60∘, expressions for sec 60 and cosec 60 is