Question

A student adds two numbers together. How can the student determine the number of significant figures in the answer?

A student measures her height with a meter stick and finds that she is about 1.5 m tall. How can she measure her height with greater accuracy and precision?

Student measures the length, width, and height of a fish tank. She finds that the fish tank is 105 cm long, 75 cm wide, and 80.5 cm high. What is the volume of the fish tank? Show your work. Use scientific notation and show the correct number of significant figures in your answer.

Answer 1

∧Answer

When adding or subtracting, use the least number of significant figures past the decimal point when adding or subtracting numbers.Example, the answer to 123.45 + 543.2 should have 1 significant figure past the decimal point.

Precision of the measuring instrument can be increased by calibration and use of proper techniques.Calibration is performed to ensure the instrument used properly measure the unit.All measuring instruments require proper calibration to give precise results.

The accuracy of the measurement can be increased through;

• Using appropriate measuring too in relation to what is being measured. I. e use a tape

• Controlling all other potential variables which could affect the measurement.

• Repeating the measurement to check if you get identical vales every time.

Volume of the fish tank is given by

V=L×W×H where L is length of tank, W is width of tank and H is height of tank.

V=105×75×80.5=633937.5 cm³

or 6.33937 × 10^5cm³

Answer 2

Answers

Question 1

After adding the two numbers together, you will find a number. To determine the number of significant figures, count the digits from right to left. The zeros on the left end and the right end are not significant. The zeros between the non-zero digits are significant.

Question 2

A mete stick is shorter than the student. So by using it, she will be force to take the measurements twice then add then together to get her height. This increases the chances of making errors. To improve the accuracy she should change the measuring instrument and use a tape measure. This will allow her to make only one measurement.

Question 3

Volume = length × width × height

= 105 × 75 × 80.5

= 633,937.5 cm³

In scientific notation;

633,937.5 cm³ = 6.339375 × 10⁵ cm³