An astronomer studying a distant cluster of galaxies finds that several of the galaxies are spiral shaped, with a nuclear region of moderate size and moderately wound arms. how should the astronomer classify these galaxies?

Sb

Astronomer Edwin Hubble invented a morphological classification of galaxies. According to its form, galaxies fall into four major types: spiral, barred spiral, elliptical and irregular. Spiral galaxies are the ones who have a bulge at the center and contains spiral arms. The galaxies that are spiral-shaped, with a nuclear region of moderate size and moderately wound arms are classified under Hubble classification as Sb.

the answer would be the third option, "no, ariel should have added 9^2 and 12^2 and compared that to 15^2."

this is found through the pythagorean theorem, which is a^2 + b^2 = c^2.

this is the correct way of solving the problem:

9^2 + 12^2 = 15^2

81 + 144 = 225

225 = 225