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Finding the Fourth Proportional to 876.61, 1,209.71 and 478.28

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Solution

The fourth proportional to 876.61, 1,209.71 and 478.28 is: 660.01

Step by Step Solution

  1. Step 1: Write the proportion equation
    876.61 : 1,209.71 = 478.28 : x
  2. Step 2: Convert to fraction form
    876.61/1,209.71 = 478.28/x
  3. Step 3: Cross multiply
    876.61x = 1,209.71 × 478.28
  4. Step 4: Simplify right side
    876.61x = 578,571.66
  5. Step 5: Solve for x
    x = 578,571.66/876.61
  6. Step 6: Final answer
    x = 660.01

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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.