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Finding the Fourth Proportional to 2,166, 2,989.14 and 1,221.78

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Solution

The fourth proportional to 2,166, 2,989.14 and 1,221.78 is: 1,686.09

Step by Step Solution

  1. Step 1: Write the proportion equation
    2,166 : 2,989.14 = 1,221.78 : x
  2. Step 2: Convert to fraction form
    2,166/2,989.14 = 1,221.78/x
  3. Step 3: Cross multiply
    2,166x = 2,989.14 × 1,221.78
  4. Step 4: Simplify right side
    2,166x = 3,652,071.47
  5. Step 5: Solve for x
    x = 3,652,071.47/2,166
  6. Step 6: Final answer
    x = 1,686.09

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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.