Digits, Grade 8, Volume 1, Homework Helper

1-6: TEKS Practice

  • 1. If x = 36 and y = 25, is square root of x plus y end root rational or irrational? Simplify your answer.

  • 2. After an accident, police can use the formula v equals 2 , square root of 5 l end root to estimate the speed, v, in miles per hour, that a car was traveling by measuring the length of the skid marks, L, in feet.

    • a. Estimate the speed of a car that left skid marks 65 ft long. Round to the nearest tenth as needed.

    • b. If the posted speed limit is 40 mi/h, was the car speeding?

  • 3. Write 0.87 as a fraction in simplest form.

  • 4. Write 0. , 72 bar as a fraction in simplest form.

  • 5. Is square root of x squared , plus , y squared end root rational or irrational when x = 14 and y = 8? If you pick a whole number value for x, can you always find a whole number value for y to make the expression a rational number? Explain.

  • 6. A couple wants to enclose a square garden with area 141 ft2. The wife says that they need about 47.6 ft of fence. The husband disagrees. He says they need about 11.9 ft of fence.

    • a. Who is correct?

    • b. What error did the person who found the incorrect length make?

      • A. The person divided the area of the garden by 4 to find the side length.

      • B. The person added 4 to the side length instead of multiplying by 4 to find the perimeter.

      • C. The person squared the area instead of finding the square root to find the side length.

      • D. The person found the side length of the garden, not the perimeter.

    • c. Explain how you found the correct length of fence that the couple needs.

  • 7. Think About the Process The length of a rectangle is twice the width. The area of the rectangle is 90 square units. Notice that you can divide the rectangle into two squares with equal area.

    • a. How can you estimate the side length of each square?

      • A. Estimate square root of 90 over 4 end root , . .

      • B. Estimate square root of 90 . .

      • C. Estimate square root of 45 . .

      • D. Estimate square root of 45 over 4 end root , . .

    • b. Estimate the length and width of the rectangle.

  • 8. Error Analysis Your teacher asks you to write 5.75 × 10−4 in standard form. Your classmate gives an incorrect answer of 0.0000575.

    • a. Write 5.75 × 10−4 in standard form.

    • b. What was your classmate's likely error?

      • A. Your classmate moved the decimal point 1 extra place to the left.

      • B. Your classmate moved the decimal point 2 extra places to the left.

      • C. Your classmate moved the decimal point 1 extra place to the right.

      • D. Your classmate moved the decimal point 2 extra places to the right.


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Table of Contents

Digits, Grade 8, Volume 1, Homework Helper Unit A: Number and Operations Unit B: Proportionality Unit C: Expressions, Equations, and Relationships English/Spanish Glossary Formulas Math Symbols Formulas Measures Properties