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Finding the Fourth Proportional to 1,212.40, 1,819.95 and 939.70

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Solution

The fourth proportional to 1,212.40, 1,819.95 and 939.70 is: 1,410.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,212.40 : 1,819.95 = 939.70 : x
  2. Step 2: Convert to fraction form
    1,212.40/1,819.95 = 939.70/x
  3. Step 3: Cross multiply
    1,212.40x = 1,819.95 × 939.70
  4. Step 4: Simplify right side
    1,212.40x = 1,710,207.02
  5. Step 5: Solve for x
    x = 1,710,207.02/1,212.40
  6. Step 6: Final answer
    x = 1,410.60

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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.