The sum of two consecutive even numbers is 174. Find the smaller number.

To find the smaller of two consecutive even numbers whose sum is 174, we can set up a simple algebraic equation.

Let the smaller even number be represented by $x$.
Since consecutive even numbers differ by 2, the next consecutive even number (the larger one) will be $x+2$.

According to the problem, the sum of these two consecutive even numbers is 174. We can write this relationship as:

$x+(x+2)=174$

Now, we simplify the equation by combining like terms:

$2x+2=174$

Subtract 2 from both sides of the equation to isolate the term with $x$:

$2x=174-2$
$2x=172$

Divide both sides by 2 to solve for $x$:

$x=\frac{172}{2}$
$x=86$

Thus, the smaller even number is 86. (The larger consecutive even number would be $86+2=88$, and their sum is indeed $86+88=174$).

Therefore, the correct option is 86.