(Originais Teachy 2023) - Question Hard of Mathematics

Rafaela started making a map of her neighborhood, which she wanted to divide into equal squares to represent the blocks. However, the streets in the neighborhood form a pattern that does not fit perfectly into squares and rectangles, making the task more challenging. She knows that the footage of each block is very important for the urbanization plans and needs to calculate the area of each space delimited by the streets. For this, she decided to use a grid and estimate the measurements of each square or rectangle formed by the streets. Considering that the streets are represented by lines that delimit the blocks of Rafaela's neighborhood and that Rafaela needs to calculate the area of a space with the lateral measurements being 'x' squares of size 'a' and 'y' squares of size 'b', where 'a' is different from 'b', determine the correct formula to calculate the area of this space on Rafaela's neighborhood grid.