1. **State the problem:** We have a sequence where each term is obtained by adding 4 to the previous term and then dividing by 2. The sequence is: $\square$, 6, 5, 4.5, ... and we need to find the first term (the empty red hexagon). 2. **Write the formula:** If $a_n$ is the $n$th term, then the rule is: $$a_{n} = \frac{a_{n-1} + 4}{2}$$ 3. **Use the given terms:** We know $a_2 = 6$, $a_3 = 5$, $a_4 = 4.5$. We want to find $a_1$. 4. **Find $a_1$ using $a_2$:** $$a_2 = \frac{a_1 + 4}{2}$$ Multiply both sides by 2: $$2a_2 = a_1 + 4$$ Substitute $a_2 = 6$: $$2 \times 6 = a_1 + 4$$ $$12 = a_1 + 4$$ Subtract 4 from both sides: $$12 - 4 = a_1$$ $$8 = a_1$$ 5. **Check with next terms:** Calculate $a_3$ from $a_2$: $$a_3 = \frac{a_2 + 4}{2} = \frac{6 + 4}{2} = \frac{10}{2} = 5$$ Calculate $a_4$ from $a_3$: $$a_4 = \frac{a_3 + 4}{2} = \frac{5 + 4}{2} = \frac{9}{2} = 4.5$$ These match the given sequence, confirming our answer. **Final answer:** The first term $a_1$ is **8**.