Final answer:
The word 'equilateral' means having equal sides; the sentence with parallelism is 'At the garage sale, we sold old, used, and unwanted items;' and the best transition for comparing ideas in an essay is 'likewise.'
Step-by-step explanation:
The best meaning for the word equilateral in the given sentence is 'D. having equal sides.' The Latin root -equi- means 'equal,' and in the context of geometry, 'lateral' refers to sides. Therefore, equilateral describes a shape whose sides are all of equal length, such as a square or equilateral triangle.
Regarding the sentence that contains parallelism, the correct answer is 'd.) At the garage sale, we sold old, used, and unwanted items.' This sentence demonstrates parallelism through the use of adjectives in a list to describe the items sold.
For establishing coherence in a compare-and-contrast essay, the transition that would best show a comparison between ideas is 'b.) likewise.' This transition word is used to highlight similarities between the subjects being compared.