Dda : aDD : : Rrb :?

Backward order letter positions are multiplied to get the second term.
TZW = 7 x 1 x 4 = 28
Similarly,
QYS = 10 x 2 x 8 = 160

Backward order letter position have been put for each letter. Let us see
T G V L
? ? ? ?
7 20 5 15
Similarly,
G P A E
? ? ? ?
20 11 26 22

A rectangle has four sides while an octagon has eight sides i.e, second has double side than first. similarly, triangle has three sides while a hexagon has six sides.

Chisel is a tool of carpenter. Similarly, anvil is a tool of cobbler.

'Table' comes under 'Furniture'. Similarly, 'Pencil' comes under 'Stationery'.

First is the sound produced by second.

First is the currency of the country denoted by second.

Second is a part of the first

As in Rare and Bare, 'r' have come to the end and 'e' has come to the second place. Similarly, in Dare 'r' will come to the end and 'e' would come to the second position. So, it will become Dear.

As in 'Bit' and 'sit' , 'ea' has come in place of 'i' Similarly in 'Hit' it will be replaced by 'ea' to make it Heat.