Hi David,

Percentage questions like this are straightforward to translate into an equation if you read the sentence carefully and compare it to reading an equation. When you read an equation, for example 5x = 6 "five x is equal to 6", you realize that the equal sign is the verb. Thus from your sentence

The saddle height on a bicycle should be 109% of the inside leg measurement of the rider

I see

The saddle height on a bicycle = 109% of the inside leg measurement of the rider

Next, "of" is multiplication ("one half of 12 is 6" is "1/2 × 12 = 6"), and thus your sentence is

The saddle height on a bicycle = 109% × the inside leg measurement of the rider

To make the notation simpler let S be the saddle height of the bicycle and I be the inside leg measurement of the rider. Hence we have

S = 109% × I

Finally 109% is 109/100 = 1.09 so

S = 1.09 × I

Harley