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Finding the Fourth Proportional to 809.79, 1,214.07 and 399.12

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Solution

The fourth proportional to 809.79, 1,214.07 and 399.12 is: 598.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    809.79 : 1,214.07 = 399.12 : x
  2. Step 2: Convert to fraction form
    809.79/1,214.07 = 399.12/x
  3. Step 3: Cross multiply
    809.79x = 1,214.07 × 399.12
  4. Step 4: Simplify right side
    809.79x = 484,559.62
  5. Step 5: Solve for x
    x = 484,559.62/809.79
  6. Step 6: Final answer
    x = 598.38

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.