Solve the Equation: Triangle Symbol + 79 = 89

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

• Step 1: Identify the equation given as $\triangle + 79 = 89$.
• Step 2: Solve for the unknown variable $\triangle$.

Now, let's work through each step:
Step 1: Observe that the equation is structured as an addition problem with an unknown symbol $\triangle$.
Step 2: To isolate $\triangle$, perform the subtraction $89 - 79$ on the right side of the equation:

$\triangle = 89 - 79$

Perform the subtraction:

$89 - 79 = 10$

Thus, the numerical value of the triangle ($\triangle$) is $10$.