By Alternendo Property, for four numbers $a, b, c, d$ if $a:b=c:d$, then  $a:c=$  .

In water, The ratio of the mass of hydrogen to the mass of oxygen is always _____.

If $\left(x+3\right):27::1:3$, then find the value of $x$.

The cost of milk per litre is $₹15$. Draw the graph for the relation between the quantity and cost. Hence find the cost of $3$ litres of milk..

If $8:14::x:28$, then find the value of $x$.

The cost of milk per litre is $₹15$. Draw the graph for the relation between the quantity and cost. Hence find the proportionality constant.

Using properties of proportion solve for $x$, given

$\frac{\sqrt{5x}+\sqrt{2x-6}}{\sqrt{5x}-\sqrt{2x-6}}=4$

If $\frac{\left[a+b-c\right]}{\left[a+b\right]}=\frac{\left[b+c-a\right]}{\left[b+c\right]}=\frac{\left[c+a-b\right]}{\left[c+a\right]}$ and $a+b+c\ne 0$ then prove that $a=b=c$.

The compound ratio of $ab : c^2$, $bc : a$ and $ca : b^2$ is $1 : 1.$

Using properties of proportion, solve for $x$, where $x$ is a positive number:

$\frac{2x+\sqrt{4x^2-1}}{2x-\sqrt{4x^2-1}}=4$

Using properties of proportion find $x:y$, given:

$\frac{x^2+2x}{2x+4}=\frac{y^2+3y}{3y+9}$