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Finding the Fourth Proportional to 1,235.96, 1,854.78 and 687.80

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Solution

The fourth proportional to 1,235.96, 1,854.78 and 687.80 is: 1,032.17

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,235.96 : 1,854.78 = 687.80 : x
  2. Step 2: Convert to fraction form
    1,235.96/1,854.78 = 687.80/x
  3. Step 3: Cross multiply
    1,235.96x = 1,854.78 × 687.80
  4. Step 4: Simplify right side
    1,235.96x = 1,275,717.68
  5. Step 5: Solve for x
    x = 1,275,717.68/1,235.96
  6. Step 6: Final answer
    x = 1,032.17

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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.