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Finding the Fourth Proportional to 1,265.91, 1,899.47 and 688.78

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Solution

The fourth proportional to 1,265.91, 1,899.47 and 688.78 is: 1,033.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,265.91 : 1,899.47 = 688.78 : x
  2. Step 2: Convert to fraction form
    1,265.91/1,899.47 = 688.78/x
  3. Step 3: Cross multiply
    1,265.91x = 1,899.47 × 688.78
  4. Step 4: Simplify right side
    1,265.91x = 1,308,317.17
  5. Step 5: Solve for x
    x = 1,308,317.17/1,265.91
  6. Step 6: Final answer
    x = 1,033.50

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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.