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Finding the Fourth Proportional to 809.86, 1,117.47 and 478.16

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Solution

The fourth proportional to 809.86, 1,117.47 and 478.16 is: 659.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    809.86 : 1,117.47 = 478.16 : x
  2. Step 2: Convert to fraction form
    809.86/1,117.47 = 478.16/x
  3. Step 3: Cross multiply
    809.86x = 1,117.47 × 478.16
  4. Step 4: Simplify right side
    809.86x = 534,329.46
  5. Step 5: Solve for x
    x = 534,329.46/809.86
  6. Step 6: Final answer
    x = 659.78

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.