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Finding the Fourth Proportional to 1,371.28, 1,892.40 and 840.32

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Solution

The fourth proportional to 1,371.28, 1,892.40 and 840.32 is: 1,159.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,371.28 : 1,892.40 = 840.32 : x
  2. Step 2: Convert to fraction form
    1,371.28/1,892.40 = 840.32/x
  3. Step 3: Cross multiply
    1,371.28x = 1,892.40 × 840.32
  4. Step 4: Simplify right side
    1,371.28x = 1,590,221.57
  5. Step 5: Solve for x
    x = 1,590,221.57/1,371.28
  6. Step 6: Final answer
    x = 1,159.66

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.