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Finding the Fourth Proportional to 1,389.72, 2,083.80 and 905.88

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Solution

The fourth proportional to 1,389.72, 2,083.80 and 905.88 is: 1,358.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,389.72 : 2,083.80 = 905.88 : x
  2. Step 2: Convert to fraction form
    1,389.72/2,083.80 = 905.88/x
  3. Step 3: Cross multiply
    1,389.72x = 2,083.80 × 905.88
  4. Step 4: Simplify right side
    1,389.72x = 1,887,672.74
  5. Step 5: Solve for x
    x = 1,887,672.74/1,389.72
  6. Step 6: Final answer
    x = 1,358.31

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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.