90 Degrees or Right Angle

Q.

A quarter-turn of a ray OA about O describes a __________ angle.

Q. A right angle is an angle of exactly 90° (degrees), corresponding to a quarter turn.

1. False
2. True

Q. If line $AB$ and $BC$ make angle ${90}^o$ between each them, then these lines will be known as -

1. Perpendicular Lines
2. Parallel Lines
3. Coinciding lines
4. None of the above.

Q. Two acute angles may form -

1. Right Angle $\left({90}^o\right)$
2. Obtuse Angle
3. Straight Angle $\left({180}^o\right)$
4. Another Acute Angle

Q. What is the value of $\sqrt{x+y}$

1. $3$
2. $-3$
3. $9$
4. $-9$

Q. In the figure given below, if $\angle ABC={90}^o,$ what is the value of $x?$

1. ${30}^o$
2. ${20}^o$
3. ${25}^o$
4. ${15}^o$