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Finding the Fourth Proportional to 918.30, 1,377.45 and 431.91

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Solution

The fourth proportional to 918.30, 1,377.45 and 431.91 is: 647.87

Step by Step Solution

  1. Step 1: Write the proportion equation
    918.30 : 1,377.45 = 431.91 : x
  2. Step 2: Convert to fraction form
    918.30/1,377.45 = 431.91/x
  3. Step 3: Cross multiply
    918.30x = 1,377.45 × 431.91
  4. Step 4: Simplify right side
    918.30x = 594,934.43
  5. Step 5: Solve for x
    x = 594,934.43/918.30
  6. Step 6: Final answer
    x = 647.87

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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.