How do i use cross multiplication to decide wheather a proportion is true or false?
3/4 = 15/16
3 * 16 =?? 4 * 15
4 * 15= 60
3 * 16= 48
now what i do? how do i know if its true or fasle?
Does 60 = 48??
Oh okay.. the number has to be the same in order for it to be true. So this problem would be false
Right. By cross-multiplying, you've proved this proportion to be false.
To use cross multiplication to determine if a proportion is true or false, follow these steps:
Step 1: Write the given proportion in the form of two fractions equated to each other. In this case, the given proportion is:
3/4 = 15/16
Step 2: Cross multiply by multiplying the numerator of the first fraction (3) with the denominator of the second fraction (16), and then multiply the numerator of the second fraction (15) with the denominator of the first fraction (4). This can be represented as follows:
3 * 16 = 15 * 4
Step 3: Simplify both sides of the equation and evaluate:
48 = 60
Step 4: Compare the simplified equation. If the two sides of the equation are equal, then the original proportion is true. If the two sides are not equal, then the original proportion is false.
In this case, since 48 is not equal to 60, the original proportion 3/4 = 15/16 is false.
So, using cross multiplication, we can determine that the given proportion is false.