Портной подогнал выкройку по меркам.

according to

Breakdown of Портной подогнал выкройку по меркам.

• портной: the tailor
• мерка: the body measurement
• выкройка: the sewing pattern

Questions & Answers about Портной подогнал выкройку по меркам.

Why is выкройку ending in -у?

Because выкройка is a feminine noun, and here it is the direct object of the verb подогнал.

• Dictionary form: выкройка
• Accusative singular: выкройку

In Russian, feminine nouns ending in -а usually change to -у in the accusative singular when they are direct objects.

So:

• Портной = the subject
• подогнал = the action
• выкройку = the thing being adjusted

Why is it по меркам and not по мерки or по мерках?

Because the preposition по here requires the dative case, and меркам is the dative plural of мерка.

• Dictionary form: мерка = a measurement
• Dative plural: меркам

So по меркам means something like:

• according to the measurements
• based on the measurements

This is a very common pattern:

• по плану = according to the plan
• по правилам = according to the rules
• по рецепту = according to the recipe