Calculate Rectangle Perimeter: ABCD with Sides 10.5 and 13

To solve this problem, we'll follow these steps:

• Step 1: Gather the given side lengths of quadrilateral ABCD.

• Step 2: Since it's necessary to understand summation, add all lengths.

• Step 3: Conclude from sum.

Now, let's work through each step:

Step 1: The problem provides:
$\begin{aligned} AB &= 10.5, \\ CD &= 13, \\ AC &= 7.5, \\ BD &= 7.5. \end{aligned}$

Step 2: Add them together:
$\begin{aligned} \text{Perimeter} &= AB + CD + AC + BD \\ &= 10.5 + 13 + 7.5 + 7.5. \end{aligned}$

Step 3: Calculate: $\begin{aligned} \text{Perimeter} &= 10.5 + 13 + 7.5 + 7.5 = 38.5. \end{aligned}$

Therefore, the solution is that the perimeter of quadrilateral ABCD is $38.5$ .