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Finding the Fourth Proportional to 1,861, 2,792.78 and 645

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Solution

The fourth proportional to 1,861, 2,792.78 and 645 is: 967.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,861 : 2,792.78 = 645 : x
  2. Step 2: Convert to fraction form
    1,861/2,792.78 = 645/x
  3. Step 3: Cross multiply
    1,861x = 2,792.78 × 645
  4. Step 4: Simplify right side
    1,861x = 1,801,343.10
  5. Step 5: Solve for x
    x = 1,801,343.10/1,861
  6. Step 6: Final answer
    x = 967.94

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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.