Determine the meter of the following line.

Galloping madly he quickly arrived.

trochaic

iambic

anapestic

dactylic

The meter of this line is dactylic.

A dactyl consists of one stressed syllable which is followed by two unstressed syllables. So here, I will write the stressed syllables as "-" and unstressed as "U".

Galloping madly he quickly arrived = - UU-UU-UU-

Ga - is stressed, lop and ing are not. Mad is stressed, ly and he are not. Quick is stressed, ly and a are not. Rived is stressed.

Anapest has one unstressed syllable followed by two stressed ones. Trochee and iamb refer to two syllables, not three.