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Finding the Fourth Proportional to 876.78, 1,314.45 and 390.30

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Solution

The fourth proportional to 876.78, 1,314.45 and 390.30 is: 585.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    876.78 : 1,314.45 = 390.30 : x
  2. Step 2: Convert to fraction form
    876.78/1,314.45 = 390.30/x
  3. Step 3: Cross multiply
    876.78x = 1,314.45 × 390.30
  4. Step 4: Simplify right side
    876.78x = 513,029.84
  5. Step 5: Solve for x
    x = 513,029.84/876.78
  6. Step 6: Final answer
    x = 585.13

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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.