First we have to know what is terminating decimal. Terminating decimal is the number which has digits that do not go on forever.

(i)

Denominator 80 has factors = 2 × 2 × 2 × 2 × 5

So, 80 has no prime factors other than 2 and 5, thus is terminating decimal.

(ii)

Denominator 24 has factors = 2 × 2 × 2 × 3

So, 24 has factors other than 2 and 5, thus is not a terminating decimal.

(iii)

Denominator 12 has factors = 2 × 2 × 3

So, 12 has factors other than 2 and 5, thus is not a terminating decimal.

(iv)

Denominator 35 has factors = 5 × 7

So, 35 has factors other than 2 and 5, thus is not a terminating decimal.

(v)

Denominator 24 has factors = 5 × 5 × 5

So, 125 has no prime factors other than 2 and 5, thus is a terminating decimal.