Decagon

A decagon is a polygon with 10 sides and 10 angles. The sum of the interior angles of a decagon is 1440 degrees. Each interior angle of a regular decagon measures 144 degrees.

Properties of a Decagon:

A decagon has 10 sides.
A decagon has 10 angles.
The sum of the interior angles of a decagon is 1440 degrees.
Each interior angle of a regular decagon measures 144 degrees.
A decagon can be regular or irregular.

Formulas for Decagon:

Sum of interior angles = (n-2) * 180 degrees, where n is the number of sides
Each interior angle of a regular decagon = Sum of interior angles / number of sides

Example Problem:

Calculate the measure of each interior angle of a regular decagon.

Given: Number of sides (n) = 10

Using the formula, each interior angle of a regular decagon = (Sum of interior angles) / (Number of sides) = 1440 / 10 = 144 degrees

Study Guide:

Understand the definition of a decagon as a polygon with 10 sides and 10 angles.
Memorize the formula for finding the sum of the interior angles of a decagon.
Practice finding the measure of each interior angle of a regular decagon using the formula.
Identify and differentiate between regular and irregular decagons.

With this study guide, you can now confidently understand and work with the properties and formulas related to decagons!

◂Math Worksheets and Study Guides First Grade. Place Value

Vocabulary/Answer key

Place Value

Vocabulary/Answer key

Place Value

The resources above cover the following skills:

Number and Operations (NCTM)

Understand numbers, ways of representing numbers, relationships among numbers, and number systems.

Use multiple models to develop initial understandings of place value and the base-ten number system.

Develop a sense of whole numbers and represent and use them in flexible ways, including relating, composing, and decomposing numbers.

Connect number words and numerals to the quantities they represent, using various physical models and representations.

Grade 1 Curriculum Focal Points (NCTM)

Number and Operations: Developing an understanding of whole number relationships, including grouping in tens and ones

Children compare and order whole numbers (at least to 100) to develop an understanding of and solve problems involving the relative sizes of these numbers. They think of whole numbers between 10 and 100 in terms of groups of tens and ones (especially recognizing the numbers 11 to 19 as 1 group of ten and particular numbers of ones). They understand the sequential order of the counting numbers and their relative magnitudes and represent numbers on a number line.