Mathematics
Grade 10
15 min
Percent error: area and volume
Percent error: area and volume
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1
Introduction & Learning Objectives
Learning Objectives
Define absolute, relative, and percent error.
Determine the upper and lower bounds of a measurement given its degree of accuracy.
Calculate the maximum and minimum possible area of a 2D shape based on measurement bounds.
Calculate the maximum and minimum possible volume of a 3D shape based on measurement bounds.
Calculate the percent error for a calculated area.
Calculate the percent error for a calculated volume.
Explain how measurement errors are magnified in area and volume calculations.
Ever wonder how a tiny 1% measuring error for a pizza's radius could lead to you getting almost 2% less pizza? 🍕 Let's investigate how small errors get bigger!
This tutorial explores how a small uncertainty in a linear measurement (like length or radius)...
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Key Concepts & Vocabulary
TermDefinitionExample
Absolute ErrorThe uncertainty in a measurement, representing how far the true value could be from the measured value. It is typically half the smallest unit of measurement.A length is measured as 12 cm to the nearest centimeter. The smallest unit is 1 cm, so the absolute error is ±0.5 cm.
Upper and Lower BoundsThe maximum and minimum possible true values of a measurement, calculated by adding and subtracting the absolute error from the measured value.For a measurement of 12 cm with an absolute error of ±0.5 cm, the lower bound is 11.5 cm and the upper bound is 12.5 cm.
Measured ValueThe value of a quantity obtained directly from a measuring instrument.Measuring the side of a cube to be 5.0 cm.
Calculated ValueA value obtained by using measured values in a formula. Th...
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Core Formulas
Finding Bounds
\text{Absolute Error} = \frac{\text{Precision Unit}}{2}
To find the range of possible true values for a measurement, first determine its precision (e.g., 'to the nearest mm', 'to one decimal place'). The absolute error is half of that precision. The bounds are the measurement ± the absolute error.
Percent Error Formula
\text{Percent Error} = \frac{\text{Maximum Possible Value} - \text{Calculated Value}}{\text{Calculated Value}} \times 100\%
This formula determines the percent error in a calculated quantity like area or volume. First, find the maximum possible value using the upper bounds of your measurements. Then, compare it to the value calculated from the original measurements.
Error Propagation Rule of Thumb
\% \text{Error}_{\text...
4 more steps in this tutorial
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Sign Up Free to ContinueSample Practice Questions
Easy
According to the tutorial, what is the definition of 'Absolute Error'?
A.The difference between the maximum and minimum possible values.
B.The uncertainty in a measurement, typically half the smallest unit of measurement.
C.The measured value minus the true value.
D.The percentage difference between the calculated value and the maximum possible value.
Easy
A student measures the radius of a circle as 15.2 cm, correct to one decimal place. What is the absolute error of this measurement?
A.±1 cm
B.±0.1 cm
C.±0.05 cm
D.±0.5 cm
Easy
A length is measured as 20 cm to the nearest centimeter. Which of the following represents the correct lower and upper bounds for the true length?
A.[19.5 cm, 20.5 cm]
B.[19 cm, 21 cm]
C.[19.9 cm, 20.1 cm]
D.[19.95 cm, 20.05 cm]
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