In the  given figure , triangle s ABC and DEF are  similar. The  are a of triangle  ABC is 9 sq. cm and the  are a of triangle  DEF is 16 sq. cm. If BC = 2.1 cm find the  length of EF.

1) 4.9 cm 
2) 6.8 cm
3) 2.8 cm
4) 9.4 cm

   If TP and TQ are  two tangents to a circle  with centre  O so that angle  POQ = 110° then angle PTQ is equal to

1) 60° 
2) 80°
3) 70°
4) 90°

To draw a pair of tange nts to a circle  which are  incline d to e ach othe r at an angle  of 45° it is re quire d to draw tange nts at the  e nd point of those  two radii of the  circle , the  angle  be twe e n which is :

1) 105° 
2) 135°
3) 145°
4) 70°

 A point O is at a distance  of 10 cm from the  centre  of a circle  of radius 6 cm. How many tangents can be  drawn from point O to the  circle ?

1) 1 
2) 3
3) infinite
4) 2

If every side of a triangle is doubled, then increase in the area of the triangle is 

1) 100Ö2 % 
2) 200  %
3) 300  %
4) 400  %