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Finding the Fourth Proportional to 917.20, 1,376 and 430

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Solution

The fourth proportional to 917.20, 1,376 and 430 is: 645.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    917.20 : 1,376 = 430 : x
  2. Step 2: Convert to fraction form
    917.20/1,376 = 430/x
  3. Step 3: Cross multiply
    917.20x = 1,376 × 430
  4. Step 4: Simplify right side
    917.20x = 591,680
  5. Step 5: Solve for x
    x = 591,680/917.20
  6. Step 6: Final answer
    x = 645.09

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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.