Which of the undefined terms is used to define the term parallel lines

Aresearch company wants to test the claim that a new multivitamin to improve short term memory. state the objective of the experiment, suggest a population, determine the experimental and control groups, and describe a sample procedure.

Luis has a cooler filled with cans of soda.for every 5 cans of coke there are 3 cans of sprite.if there are 25 cans of coke, how mant cans of sprite are there?

The floor of a building consists of 3000 tiles which are rhombus shaped and each of it's diagonals are 45 cm and 30 cm in length. find the total cost of polishing the floor, if the cost per m² is rs. 4.