**Vocabulary**

Pythagorean Theorem, theorem

**TEKS** 8(1)(C), 8(7)(C), 8(7)(D)

**Example Using Distance to Locate Points**

Point *B* has coordinates (1, 5). The *y*-coordinate of point *A* is −3. The distance between point *A* and point *B* is 10 units. What are the possible coordinates of point *A*?

**Solution**

Point *B* has coordinates (1, 5).

Point *A* has *y*-coordinate of −3, so it is somewhere along the line *y* = −3.

Points *A*, *B*, and *C* form a right triangle with

The distance between points *A* and *B* is 10 units. The length of

Use the Pythagorean Theorem to find the length of the unknown leg.

Point *A* can be 6 units to the left of point *C*, or 6 units to the right of point *C*. So the possible coordinates of point *A* are (−5, −3) and (7, −3).

Digits, Grade 8, Volume 1, Homework Helper
Unit A: Number and Operations
Math Symbols
Formulas Measures
Properties

Topic 1: Rational and Irrational Numbers

Unit B: Proportionality
- 1-1: Exploring Irrational Numbers
- 1-1: TEKS Practice
- 1-2: Approximating Irrational Numbers
- 1-2: TEKS Practice
- 1-3: Comparing and Ordering Rational and Irrational Numbers
- 1-3: TEKS Practice
- 1-4: Exploring Scientific Notation
- 1-4: TEKS Practice
- 1-5: Using Scientific Notation to Describe Very Large Quantities
- 1-5: TEKS Practice
- 1-6: Additional Problem Solving
- 1-6: TEKS Practice

Topic 2: Proportional Relationships, Lines, and Linear Equations
Topic 3: Defining and Comparing Functions

Unit C: Expressions, Equations, and Relationships
- 2-1: Representing Proportional Relationships
- 2-1: TEKS Practice
- 2-2: Linear Equations: y = mx
- 2-2: TEKS Practice
- 2-3: The Slope of a Line
- 2-3: TEKS Practice
- 2-4: Unit Rates and Slope
- 2-4: TEKS Practice
- 2-5: The y-intercept of a Line
- 2-5: TEKS Practice
- 2-6: Linear Equations: y = mx + b
- 2-6: TEKS Practice
- 2-7: Distinguishing Between Proportional and Non-Proportional Situations
- 2-7: TEKS Practice
- 2-8: Additional Problem Solving
- 2-8: TEKS Practice

Topic 4: Using the Pythagorean Theorem
Topic 5: Surface Area and Volume
Topic 6: Linear Equations in One Variable
Topic 7: Reasoning in Geometry
Topic 8: Simultaneous Linear Equations

English/Spanish Glossary
Formulas
- 7-1: Angles, Lines, and Transversals
- 7-1: TEKS Practice
- 7-2: Reasoning and Parallel Lines
- 7-2: TEKS Practice
- 7-3: Interior Angles of Triangles
- 7-3: TEKS Practice
- 7-4: Exterior Angles of Triangles
- 7-4: TEKS Practice
- 7-5: Angle–Angle Triangle Similarity
- 7-5: TEKS Practice
- 7-6: Additional Problem Solving
- 7-6: TEKS Practice

- 8-1: What are Simultaneous Linear Equations in Two Variables?
- 8-1: TEKS Practice
- 8-2: Estimating Solutions of Simultaneous Linear Equations by Inspection
- 8-2: TEKS Practice
- 8-3: Solving Simultaneous Linear Equations by Graphing
- 8-3: TEKS Practice
- 8-4: Solving Simultaneous Linear Equations Using Substitution
- 8-4: TEKS Practice
- 8-5: Additional Problem Solving
- 8-5: TEKS Practice