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Finding the Fourth Proportional to 1,017.96, 1,404.90 and 645

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Solution

The fourth proportional to 1,017.96, 1,404.90 and 645 is: 890.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,017.96 : 1,404.90 = 645 : x
  2. Step 2: Convert to fraction form
    1,017.96/1,404.90 = 645/x
  3. Step 3: Cross multiply
    1,017.96x = 1,404.90 × 645
  4. Step 4: Simplify right side
    1,017.96x = 906,160.50
  5. Step 5: Solve for x
    x = 906,160.50/1,017.96
  6. Step 6: Final answer
    x = 890.17

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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.