# Changing The Subject - Odd One Out

## Which of the five versions of the formula is the odd one out because it is not equivalent to the other four?

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This is level 5; Formulas including squares or square roots. You can earn a trophy if you answer the questions correctly.

 A$$b=\sqrt a$$ B$$b = \frac ab$$ C$$\frac{a}{b^2}=1$$ D$$b=2a$$ E$$a=b^2$$
 A$$\frac{A}{\pi}=r^2$$ B$$A=\pi r^2$$ C$$r=\sqrt{\frac{A}{\pi}}$$ D$$\pi = \frac{A}{r^2}$$ E$$A=\sqrt{\frac{r^2}{\pi}}$$
 A$$h=\frac{V}{\pi r^2}$$ B$$r=\sqrt{\frac{V}{\pi h}}$$ C$$V=\pi r^2 h$$ D$$r^2=\frac{V}{h \pi}$$ E$$r=\frac{V}{\pi h}$$
 A$$a^2=b^2+c^2$$ B$$a^2=b^2-c^2$$ C$$b^2=a^2-c^2$$ D$$c^2=a^2-b^2$$ E$$a=\sqrt{b^2+c^2}$$
 A$$\pi = \frac{4V}{3r^3}$$ B$$V=\frac43 \pi r^3$$ C$$\pi = \frac{3V}{4r^3}$$ D$$r^3=\frac{3V}{4 \pi}$$ E$$3V=4 \pi r^3$$
 A$$b=\frac{a^2}{c}$$ B$$c=\frac{a^2}{b}$$ C$$b=\frac{a}{c^2}$$ D$$a=\sqrt{bc}$$ E$$a^2 = bc$$
 A$$d^2=2a+1$$ B$$d=\sqrt{2a+1}$$ C$$2a=d^2-1$$ D$$a=\frac{1-d^2}{2}$$ E$$a=\frac{d^2-1}{2}$$
 A$$p=\frac{f}{q^2}$$ B$$\frac pq = f^2$$ C$$f=\sqrt{\frac pq}$$ D$$p=f^2 q$$ E$$\frac qp = \frac{1}{f^2}$$

This is Changing The Subject - Odd One Out level 5. You can also try:
Level 1 Level 2 Level 3 Level 4 Level 6 Level 7 Level 8

## Instructions

Try your best to answer the questions above. Choose one of the five possible answers. When you have finished click the "check" button. If you have any questions wrong, do your best to do corrections but if there is anything you don't understand, please ask your teacher for help.

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## Go Maths

Learning and understanding Mathematics, at every level, requires learner engagement. Mathematics is not a spectator sport. Sometimes traditional teaching fails to actively involve students. One way to address the problem is through the use of interactive activities and this web site provides many of those. Click here for more activities designed for students in upper Secondary/High school.

## Teachers

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## Description of Levels

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Level 1 - Formulas which can be rearranged by adding or subtracting terms from both sides

Example: Make e the subject of the formula d = e - f

Level 2 - Formulas which can be rearranged by multiplying or dividing both sides by a value

Example: Rearrange the formula n = mp

Level 3 - Formulas which can be rearranged by adding, subtracting, multiplying or dividing both sides by a value

Example: Rearrange the formula b = a + cd

Level 4 - Formulas including brackets or expressions in the numerator or denominator of a fraction

Example: Rearrange the formula p = s(t + 2)

Level 5 - Formulas including squares or square roots

Example: Rearrange the formula d² = 2a + 1

Level 6 - Finding the unknown which is not the subject of a formula

Example: If m = n² + 2p, find p when m=8 and n=10

Level 7 - Rearrange the formulae where the new subject appears twice; fill in the blanks

Example: Rearrange the formula ax + b = cx + g to make x the subject

Level 8 - Rearrange the formulae where the new subject appears twice; show your working

Example: Rearrange the formula a(3-x)=5x to make x the subject

Exam Style Questions - A collection of problems in the style of GCSE or IB/A-level exam paper questions (worked solutions are available for Transum subscribers).

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## Curriculum Reference

See the National Curriculum page for links to related online activities and resources.

## Example

Make $$y$$ the subject of the following:

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