A school teacher wants to survey students at her elementary school. She surveys 20 students from each grade level. What type of sampling technique she is using

Stratified Random sampling

Step-by-step explanation:

When a random observations are selected from a number of individual groups in a particular population, the type of sampling technique is called Stratified Random sampling. Stratified Random sampling begins with the partitioning or splitting or a population into subgroups. A number of random selection are then made from each of the subgroups to form a collection of larger samples. This is different from the simple random sampling technique which makes random selection directly from a larger sample or population without prior partitioning of the population. The different grades of students represents the individual stratum from which random selections are made.

just take the area of the square and then the area of the circle then subtract the circle area from the squares area

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add a pic of the graph, then ill edit this "answer" and solve it for you : 3

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