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

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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

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Curriculum Reference

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

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