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Finding the Fourth Proportional to 1,429.70, 1,972.91 and 840.20

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Solution

The fourth proportional to 1,429.70, 1,972.91 and 840.20 is: 1,159.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,429.70 : 1,972.91 = 840.20 : x
  2. Step 2: Convert to fraction form
    1,429.70/1,972.91 = 840.20/x
  3. Step 3: Cross multiply
    1,429.70x = 1,972.91 × 840.20
  4. Step 4: Simplify right side
    1,429.70x = 1,657,624.92
  5. Step 5: Solve for x
    x = 1,657,624.92/1,429.70
  6. Step 6: Final answer
    x = 1,159.43

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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.