(i) 12 kilometer 

To convert kilometer into meter multiply by 1000.

Therefore 12 km = 12 × 1000 = 12000 meter

(ii) 10 1/2 kilometer

To convert kilometer into meter, multiply by 1000

Therefore 10 1/2 km = 10 km + 1/2 km

= 10 x 1000 meter + 1/2 x 1000 meter

= 10000 + 500 meter = 10500 meter

(iii) 25 1/4 meter

To convert meter into centimeter multiply by 100.

Therefore 25 1/4 meter

= 25 meter + 1/4 meter

= 25 x 100 cm + 1/4 x 100 cm

= 2500 cm + 25 cm

= 2525 cm.

(iv) 15 3/4 meter

To convert meter into centimeter multiply by 100

Therefore meter 15 3/4 cm. = 15 meter + 3/4 meter

= 15 x 100 cm. + 3/4 x 100 cm.

= 1500 cm. + 3 x 25 cm.

= 1500 cm. + 75 cm.

= 1575 cm.

(v) 4 1/5 cm.

To convert centimeter into millimeter multiply by 10.

Therefore 4 1/5 cm.

= 4 cm. + 1/5 cm.

= 4 x 10 mm. + 1/5 x 10 mm.

= 40 mm. + 2 mm.

= 42 mm.

(vi) 1 4/5 cm.

To convert centimeter into millimeter multiply by 10.

Therefore 1 4/5 cm. = 1 cm. + 4/5 cm

= 1 x 10 mm. + 4/5 x 10 mm.

= 10 mm. + 4 x 2 mm.

= 10 mm. + 8 mm

= 18 mm.