Answer:
square
Step-by-step explanation:
all sides have the same length 
all vertices form 90 degree angles
Cross multiply to solve proportions. The answer could also be written as 6.4
Answer:
a) cluster sampling
Step-by-step explanation:
In cluster sampling method, each member of a population is assigned to one and only one group.This means clusters are formed through probability method usually a simple random sampling.The participants in the clusters are the only one to be surveyed.
In this example, simple random sampling is used to identify 12 home rooms(cluster) where a group of 20 students (participants) in each room is given the survey.
Answer:
Step-by-step explanation:
Let's find the discriminant 

It is a positive number, therefore there are 2 solutions
3 feet 8 inches converted to inches is 3x12+8=44inches
44inches times 4 pieces is 176 inches.
176 inches converted back to feet and inches is 176/12=14 feet 8 inches so he would need 15 feet of board