Log in to add a comment

## Answers

To cross multiply is to go from this:8 = 2123 To this:8 × 3 = 12 × 2How Does it Work?Step 1: When you multiply the top and bottom of a fraction by the same amount, it doesn't change its value. Example (first fraction above): 8 = 8 × 31212 × 3In that example I multiplied the top and bottom of the first fraction

by the bottom number of the second fraction.Step 2: We could also multiply the top and bottom of the second fraction by the bottom number of the first fraction.Example (second fraction above): 2 = 2 × 1233 × 12Step 3: And we would then have:8 × 3 = 2 × 1212 × 33 × 12And Magic! The bottom of both fractions is now 12 × 3 ... ! Step 4: We can get rid of the 12 × 3 (because we are dividing both sides by the same amount) and the equation is still true:8 × 3 = 12 × 2Job Done! In practice, though, it is easier to skip the steps and go straight to the "cross-multiplied" form.Using VariablesSo far I have used numbers, but we can state it more generally using variables:To cross multiply is to go from this:a = cbd To this:ad = bc

How to remember: "cross" multiply:Example Cross multiplication can help speed up a solution. Like in this example: Find "x":x = 28x Let's cross multiply:x2 = 8 × 2 = 16 And solvex = 4 or -4

### This Is a Certified Answer

Certified answers contain reliable, trustworthy information vouched for by a hand-picked team of experts. Brainly has millions of high quality answers, all of them carefully moderated by our most trusted community members, but certified answers are the finest of the finest.

Cross multiplication is used in vector i.e. A <bar>× B<bar>= ABsinθ

eg A<bar> = a₁î<cap> +a₂j<cap> +a₃k<cap>

and B<bar> = b₁î<cap> +b₂j<cap> +b₃k<cap>

so A<bar > × B<bar> =

eg A<bar> = a₁î<cap> +a₂j<cap> +a₃k<cap>

and B<bar> = b₁î<cap> +b₂j<cap> +b₃k<cap>

so A<bar > × B<bar> =