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Finding the Fourth Proportional to 1,429.28, 1,972.40 and 839.70

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Solution

The fourth proportional to 1,429.28, 1,972.40 and 839.70 is: 1,158.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,429.28 : 1,972.40 = 839.70 : x
  2. Step 2: Convert to fraction form
    1,429.28/1,972.40 = 839.70/x
  3. Step 3: Cross multiply
    1,429.28x = 1,972.40 × 839.70
  4. Step 4: Simplify right side
    1,429.28x = 1,656,224.28
  5. Step 5: Solve for x
    x = 1,656,224.28/1,429.28
  6. Step 6: Final answer
    x = 1,158.78

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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.