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Finding the Fourth Proportional to 21,840, 30,139.20 and 11,904

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Solution

The fourth proportional to 21,840, 30,139.20 and 11,904 is: 16,427.52

Step by Step Solution

  1. Step 1: Write the proportion equation
    21,840 : 30,139.20 = 11,904 : x
  2. Step 2: Convert to fraction form
    21,840/30,139.20 = 11,904/x
  3. Step 3: Cross multiply
    21,840x = 30,139.20 × 11,904
  4. Step 4: Simplify right side
    21,840x = 358,777,036.80
  5. Step 5: Solve for x
    x = 358,777,036.80/21,840
  6. Step 6: Final answer
    x = 16,427.52

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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.