Question

Lesson 4: Proportional Relationships a 2. A recip Equations the qu a. Let's write equations describing proportional relationships. b. 4.1: Number Talk: Division Find each quotient mentally. C. 645 - 100 645:50 48.6 - 30 48.6 + x

Answer 1

$\frac{645}{100}=6.45$

Move the decimal point of 645 two units left ( You are dividing by 100)

---------------------------

$\frac{645}{50}=\frac{129}{10}=12.9$

Simplify 645/50 as 129/10, now move the decimal point of 129 one unit left (You are dividing by 10).

-----------------------

$\frac{48.6}{30}=\frac{243}{\frac{5}{30}}=\frac{243}{150}=\frac{81}{50}$

Express 48.6 as 243/5, then use division of fractions to get 243/150, then simplify 243/150 as 81/50

-----------------------

$\frac{48.6}{x}=\frac{\frac{243}{5}}{x}=\frac{243}{5x}$

Express 48.6 as 243/5, then use division of fractions to get 243/5x