First, we know that when multiplying fractions, we multiply both the numerator and denominator.
so, in 4/9 • 4/5, 4•4 = 16, and 9•5 = 45
so, 4/9 • 4/5 = 16/45. now, we’ll look for the Least Common Factor
factors are numbers that you can multiply together to = another number. the LEAST common Factor is the # that is smallest that you can divide both numbers by, in an equation and get a whole number.
for instance, 3•3 and 1•9 are the only ways to get 9, so, the factors are 1, 3, 9
let’s look for the LCF in 16 and 45. - if we find the ways to get 16, we have: 1•16, 2•8, and 4•4 so, the factors are 1, 2, 4, 8, and 16. this is called FACTORING :)
the ways to get 45 are... 1•45, 3•15, and 5•9, so the FACTORS are 1, 3, 5, 9, 15, & 45. - compare the factors of 16 & 45, none of them are the same besides 1, and we know that dividing these numbers by 1 will not do anything.
because of this, we can not reduce 16/45, so the reduced answer to 4/9 • 4/5 = 16/45
The data is a little bit complex,but you can use the knowledge of vector in the subject of algebra,or you can ultimate the basic Euclidean knowledge,like cosine theorem.In detail,you can list two equation with two variable,and get the answer.but i don't finish calculating it.