What is a Sphere?
A sphere is a three-dimensional shape that is perfectly round, like a ball. It is defined as the set of all points in space that are a given distance (the radius) away from a given point (the center).
Characteristics of a Sphere
Here are some key characteristics of a sphere:
- Surface Area: The surface area of a sphere is given by the formula: A = 4πr2, where r is the radius of the sphere.
- Volume: The volume of a sphere is given by the formula: V = (4/3)πr3, where r is the radius of the sphere.
- Diameter: The diameter of a sphere is the distance across the sphere passing through the center. It is twice the radius: d = 2r.
Real-life Examples
Spheres can be found in many real-life objects, such as balls, planets, and bubbles. Their perfectly round shape makes them ideal for minimizing surface area and maximizing volume, which is why they are commonly used in various applications.
.◂Math Worksheets and Study Guides Third Grade. Perimeter
Study Guide
Perimeter 
Activity Lesson
Area and Perimeter Worksheet/Answer key
Perimeter Worksheet/Answer key
Perimeter Worksheet/Answer key
Perimeter Worksheet/Answer key
Perimeter
Activity LessonWorksheet/Answer keyWorksheet/Answer keyWorksheet/Answer keyWorksheet/Answer keyThe resources above cover the following skills:
Geometry (NCTM)
Analyze characteristics and properties of two- and three-dimensional geometric shapes and develop mathematical arguments about geometric relationships.
Identify, compare, and analyze attributes of two- and three-dimensional shapes and develop vocabulary to describe the attributes.
Use visualization, spatial reasoning, and geometric modeling to solve problems.
Use geometric models to solve problems in other areas of mathematics, such as number and measurement.
Connections to the Grade 3 Focal Points (NCTM)
Measurement: Students in grade 3 strengthen their understanding of fractions as they confront problems in linear measurement that call for more precision than the whole unit allowed them in their work in grade 2. They develop their facility in measuring with fractional parts of linear units. Students develop measurement concepts and skills through experiences in analyzing attributes and properties of two-dimensional objects. They form an understanding of perimeter as a measurable attribute and select appropriate units, strategies, and tools to solve problems involving perimeter.