Question

Angle in a semicircle is
$
  (a){\text{ Acute angle}} \\
  (b){\text{ Straight angle}} \\
  (c){\text{ Right angle}} \\
  (d){\text{ Obtuse angle}} \\
$

Answer 1

Hint: A complete circle comprises ${360^0}$ so if we talk about a semicircle then eventually this revolution will too be halved.

Complete step-by-step answer:

The pictorial representation of the semicircle is shown above with center O.
As we know that in a complete circle the revolution at center is 3600.
Now we all know that the semicircle is half of the circle.
So it makes a revolution$ = \dfrac{{{{360}^0}}}{2} = {180^0}$.
And we all know 180 degree angles are only possible in a straight line.
So it is called a straight angle.
So an angle in a semicircle is a straight angle.
Hence option (B) is correct.

Note: Acute angle refers to the angles which are smaller than ${90^0}$. A straight line comprises of an angle ${180^0}$, angle is said to be a right angle if it is equal to ${90^0}$ and obtuse angle are angle which are greater than ${90^0}$ but are less than ${180^0}$.