If cos A=tan B,cos B=tan C,cos C=tan A,then sin A is equal to 

Consider the following statements

1.Let D be a point on the side BC of a triangle ABC.If area of a triangle ABD=area of a triangle ACD,then for all points  O on AD,area of triangle ABO=area of triangle ACO

2.If G is a point of concurrence  of medians of a triangle ABC,then the area of a triangle ABG=area of a triangle BCG=area of a triangle ACG

Which of the above statement are correct?

ABCD is a parallelogram.where AB:AD=2:1.One of the angles of a parallelogram is 60.The two diagonals are in the ratio 

If the radius of a aphere is increased by 10%,then its volume is increased by

If tan(A+B)=√3 and tan A=1,then tan(A-B) is equal to

Four equal sized maximum circular plates are cut off from a square paper sheet of area 784sq.cmThe circumference of each plate is