Mathematics Grade 8 15 min

Evaluate radical expressions

Evaluate radical expressions

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Introduction & Learning Objectives

Learning Objectives Define a radical expression, radicand, and square root. Identify the first 15 perfect squares. Evaluate the principal square root of any perfect square from 0 to 225. Estimate the value of a square root of a non-perfect square to the nearest integer. Evaluate simple expressions involving radicals using the order of operations. Evaluate the cube root of simple perfect cubes like 8, 27, and 64. Solve for the side length of a square given its area. If a square chessboard has 64 identical squares, how many squares long is one side of the board? ♟️ Let's find out how to solve this with a special symbol! In this tutorial, you will learn about radical expressions, focusing on square roots. We will explore how to find the value of square roots (a process...
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Key Concepts & Vocabulary

TermDefinitionExample Radical ExpressionAn expression that contains a radical symbol (like a square root or cube root).\sqrt{25} or 5 + \sqrt{9} Radical SymbolThe symbol (\sqrt{}) used to indicate the root of a number. For a square root, it's just \sqrt{}, and for a cube root, it's \sqrt[3]{}.In \sqrt{16}, the \sqrt{} is the radical symbol. RadicandThe number or expression found inside the radical symbol.In \sqrt{81}, the radicand is 81. Square RootA number that, when multiplied by itself, produces the radicand. The principal square root is the positive value.The square root of 36 is 6, because 6 * 6 = 36. Perfect SquareA number that is the result of an integer multiplied by itself.49 is a perfect square because it is 7 * 7 (or 7^2). Cube RootA number that, when multiplied by it...
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Core Formulas

Definition of a Square Root If a^2 = b, then \sqrt{b} = a (for a ≥ 0) This is the fundamental relationship between squaring a number and finding its square root. They are inverse operations, meaning they 'undo' each other. Order of Operations with Radicals P-E-M-D-A-S (Parentheses, Exponents, Multiplication/Division, Addition/Subtraction) Radicals (roots) are treated like exponents. You must evaluate the radical part of an expression before you do any multiplication, division, addition, or subtraction. Definition of a Cube Root If a^3 = b, then \sqrt[3]{b} = a This is the relationship between cubing a number and finding its cube root. They are also inverse operations.

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Sample Practice Questions

Challenging
A student incorrectly calculates \sqrt{9 + 16} as \sqrt{9} + \sqrt{16}. What is the difference between the correct value and the student's incorrect value?
A.0
B.1
C.2
D.5
Challenging
Evaluate the expression: (\sqrt{225} - \sqrt{25}) / \sqrt[3]{8}
A.10
B.2.5
C.20
D.5
Challenging
The side length of a square is given by the expression \sqrt{144} inches. What is the area of the square?
A.12 square inches
B.144 square inches
C.24 square inches
D.20736 square inches

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