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Finding the Fourth Proportional to 876.65, 1,209.78 and 478.31

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Solution

The fourth proportional to 876.65, 1,209.78 and 478.31 is: 660.07

Step by Step Solution

  1. Step 1: Write the proportion equation
    876.65 : 1,209.78 = 478.31 : x
  2. Step 2: Convert to fraction form
    876.65/1,209.78 = 478.31/x
  3. Step 3: Cross multiply
    876.65x = 1,209.78 × 478.31
  4. Step 4: Simplify right side
    876.65x = 578,649.87
  5. Step 5: Solve for x
    x = 578,649.87/876.65
  6. Step 6: Final answer
    x = 660.07

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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.