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Finding the Fourth Proportional to 70,028, 105,042 and 20,780

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Solution

The fourth proportional to 70,028, 105,042 and 20,780 is: 31,170

Step by Step Solution

  1. Step 1: Write the proportion equation
    70,028 : 105,042 = 20,780 : x
  2. Step 2: Convert to fraction form
    70,028/105,042 = 20,780/x
  3. Step 3: Cross multiply
    70,028x = 105,042 × 20,780
  4. Step 4: Simplify right side
    70,028x = 2,182,772,760
  5. Step 5: Solve for x
    x = 2,182,772,760/70,028
  6. Step 6: Final answer
    x = 31,170

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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.