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Finding the Fourth Proportional to 805.68, 1,208.70 and 318.78

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Solution

The fourth proportional to 805.68, 1,208.70 and 318.78 is: 478.24

Step by Step Solution

  1. Step 1: Write the proportion equation
    805.68 : 1,208.70 = 318.78 : x
  2. Step 2: Convert to fraction form
    805.68/1,208.70 = 318.78/x
  3. Step 3: Cross multiply
    805.68x = 1,208.70 × 318.78
  4. Step 4: Simplify right side
    805.68x = 385,309.39
  5. Step 5: Solve for x
    x = 385,309.39/805.68
  6. Step 6: Final answer
    x = 478.24

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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.