options: Statistics & Probability: students learn to analyze and produce data distributions, and build understanding of univariate and bivariate data. They learn to interpret data, make statistical inferences, justify conclusions, understand rules of probability, and use probability to make decisions.

Number & Operations in Base Ten: students learn to work with the base-ten system and build place value understanding.

Measurement & Data: students learn to work with data and measure attributes such as time, money, length, area, and volume. They may learn to compare measurements to operations and convert between different units of measure.

Modeling: students learn to choose and use appropriate mathematics and statistics to analyze real-world empirical situations, improve decisions, and report on their conclusions and the reasoning behind them.

Operations & Algebra: students learn to solve problems using algebraic thinking and operations such as addition, subtraction, multiplication, and division. They may learn to identify and explain arithmetic patterns, evaluate or manipulate numerical expressions, and reason with equations and inequalities.

Functions: students learn to define, use, and evaluate functions to model relationships between quantities.

Counting & Cardinality: students learn to know number names and the count sequence, count to tell the number of objects, and compare numbers.

Ratios & Proportional Relationships: students learn to recognize, describe, represent, and reason with ratios, rates, proportional relationships, and percent.

Number & Operations - Fractions: students learn to understand fractions as numbers and may work with them using addition, subtraction, multiplication, and division.

Geometry: students learn to classify geometric figures by their properties, and understand and compare the relationships between them. Students develop and use formulas to compute lengths, areas, and volumes, and they use transformations to generate new shapes and compare existing ones. Geometry can be studied with and without coordinates.

Number Systems and Quantity: students learn to understand the complex number system and reason quantitatively.
problem_activity: Task
Global Positioning System or GPS devices receive input from satellites and use
this information to locate our position on the planet.   The information received from
each individual satellite gives the distance from the GPS  device to that satellite and the location of the satellite.  The set of points at a fixed distance from a satellite form
a sphere so when the GPS receives its distance from a given satellite, this tells
us that it lies on a particular sphere.  Data from several satellites will
locate the GPS device on the intersection of spheres.  This problem examines different scenarios for intersections of spheres from the point of view of the GPS device: how many
different satellites are needed to locate the GPS device?  Does it matter how
the satellites are configured in space?
Below is a sample picture showing three satellites and their distances, $d_1, d_2, d_3$ from a point on the earth:
[IMG]
The three parts of this problem investigate different positions of the three
satellites pictured above: the goal is to find scenarios where one, two or three of the distances
$d_1$, $d_2$, $d_3$ are (or are not) sufficient to locate the GPS unit.
Give an example of a satellite and GPS location so that the GPS device can determine its location on the earth with input
from this single satellite.  Also give an example when this one signal does not provide
enough information  to designate a location on the earth.
Give  an example of a configuration of two satellites  and the GPS so that the GPS device can determine its location on the earth with input
from the two satellites (but not from either alone).   Also give an example where these two signals do not provide
enough information  to designate a location on the earth.
Give  an example of a configuration of three satellites and the GPS so that  the GPS device can determine its location on the earth with input
from three satellites (but not from any pair of the satellites).   Also give an example where three signals do not provide
enough information  to designate a location on the earth.


correct_option_index: 3

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