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Finding the Fourth Proportional to 806.21, 1,209.11 and 318.99

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Solution

The fourth proportional to 806.21, 1,209.11 and 318.99 is: 478.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    806.21 : 1,209.11 = 318.99 : x
  2. Step 2: Convert to fraction form
    806.21/1,209.11 = 318.99/x
  3. Step 3: Cross multiply
    806.21x = 1,209.11 × 318.99
  4. Step 4: Simplify right side
    806.21x = 385,694.00
  5. Step 5: Solve for x
    x = 385,694.00/806.21
  6. Step 6: Final answer
    x = 478.40

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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.