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Finding the Fourth Proportional to 78,780, 118,170 and 20,412

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Solution

The fourth proportional to 78,780, 118,170 and 20,412 is: 30,618

Step by Step Solution

  1. Step 1: Write the proportion equation
    78,780 : 118,170 = 20,412 : x
  2. Step 2: Convert to fraction form
    78,780/118,170 = 20,412/x
  3. Step 3: Cross multiply
    78,780x = 118,170 × 20,412
  4. Step 4: Simplify right side
    78,780x = 2,412,086,040
  5. Step 5: Solve for x
    x = 2,412,086,040/78,780
  6. Step 6: Final answer
    x = 30,618

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These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.