#### Answer

The two sides that are marked congruent both measure $18$. Another side measures $16.4$. The last side is already given; it measures $4.8$.

#### Work Step by Step

We can set the first set of congruent sides equal to one another to solve for $b$:
$4y + 6 = 7y - 3$
Subtract $6$ from each side of the equation to move constants to the left side of the equation:
$4y = 7y - 9$
Subtract $7y$ from each side of the equation to move the variable to the left side of the equation:
$-3y = -9$
Divide each side of the equation by $-3$ to solve for $y$:
$y = 3$
Let's plug in $3$ for $y$ to find the length of one of the sides:
length of side = $4(3) + 6$
Multiply first, according to order of operations:
length of side = $12 + 6$
Add to solve:
length of side = $18$
Let's substitute $3$ for $y$ in another expression:
length of side = $5(3) + 1.4$
Multiply first, according to order of operations:
length of side = $15 + 1.4$
Add to solve:
length of side = $16.4$
Two of the sides are congruent, so they both measure $18$. Another side measures $16.4$. The last side is already given; it measures $4.8$.