Question

Can someone explain how to do #3?

Answer 1

Remember PEMDAS ? The order of operation: Find the sqt of 2 and then raise that value to the 3rd power to get 2.828...

It wants to know the value of that operation to the nearest tenth place, the first value after the decimal. It is called tenth because the value is 1/10 of a whole (1). So 2.8

Answer 2

$\displaysyle (\sqrt 2)^{3}=(2^{\frac{1}{2}})^3=2^{\frac{1}{2} \cdot 3}=2^{\frac{3}{2}}=\sqrt {2^3}=\sqrt 8$

√8 is between 2 and 3, because 2²=4<8, but 3²=9>8. Also, our value is closer to 3 than to 2, so it is more than 2.5 and we have C and D options left.

Among these two numbers we find the one which is closer to √8.

C. 27=√729 ⇒ 2.7=√7.29

D. 28=√784 ⇒ 2.8=√7.84

Hence our answer is D) 2.8