Radius of curvature, R = 150 cm

The mirror is concave, so the focal length (f) is negative. Using the mirror equation:

1/f = 1/p + 1/q

where p is the object distance (assumed to be at infinity for a star) and q is the image distance.

Since p = ∞, the equation becomes:

1/f = 0 + 1/q

1/f = 1/q

q = f

Therefore, the image of the star is formed at the focal point of the mirror.

To find the focal length (f), we can use the formula:

f = R/2

Substituting the given value of R:

f = 150 cm / 2

f = 75 cm

Therefore, the image of the star is formed at a distance of 75 cm from the mirror.