Decimal Ratios A decimal ratio is expressed as one decimal value. For example the ratio of a 12-year-old girl’s age to her 8-year-old brother’s age is 12:8 = 12 ÷ 8 = 1.5 This value tells us that she is 1.5 times older than her brother. The result is in the ratio form of ‘decimal : 1’, but the 1 is not shown. To convert a : b to decimal form, calculate a ÷ b and express the answer as a decimal. Example 1 Convert 34 : 19 to a decimal ratio, correct to 2 decimal places 34 ÷ 19 = 1.79

Example 2 Find a if a : b = 1.57 and b =18.9 a b = a 18.9 = a = × 18.9 a = 29.67

Example 3 The ratio of a day’s maximum temperature to its minimum temperature was 2.07.

Today’s work Yesterday’s work Exercise 4.3 Page 170  171 All Qs Exercise 4.2 Page 165  168 All Qs 1 st column only