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Finding the Fourth Proportional to 1,866.72, 2,800.80 and 840

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Solution

The fourth proportional to 1,866.72, 2,800.80 and 840 is: 1,260.32

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,866.72 : 2,800.80 = 840 : x
  2. Step 2: Convert to fraction form
    1,866.72/2,800.80 = 840/x
  3. Step 3: Cross multiply
    1,866.72x = 2,800.80 × 840
  4. Step 4: Simplify right side
    1,866.72x = 2,352,672
  5. Step 5: Solve for x
    x = 2,352,672/1,866.72
  6. Step 6: Final answer
    x = 1,260.32

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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.