Calculate Gabriel's Final Grade: Weighted Average with 30%, 15%, 35%, and 20% Contributions

To calculate Gabriel's final weighted average, we'll use the formula for a weighted average:

$\text{Weighted Average} = (\text{Test 1 Grade} \times \text{Weight 1}) + (\text{Exam Grade} \times \text{Weight 2}) + (\text{Test 2 Grade} \times \text{Weight 3}) + (\text{Project Grade} \times \text{Weight 4})$

Next, calculate the contribution of each component:

• Test 1 Contribution: $84 \times 0.30 = 25.2$
• Exam Contribution: $73 \times 0.15 = 10.95$
• Test 2 Contribution: $87 \times 0.35 = 30.45$
• Project Contribution: $92 \times 0.20 = 18.4$

Now, add all these contributions to find the final weighted average:

$\text{Weighted Average} = 25.2 + 10.95 + 30.45 + 18.4 = 85$

Therefore, Gabriel's final weighted average is $\boxed{85}$.