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Finding the Fourth Proportional to 28,239, 38,970 and 15,663.78

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Solution

The fourth proportional to 28,239, 38,970 and 15,663.78 is: 21,616.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    28,239 : 38,970 = 15,663.78 : x
  2. Step 2: Convert to fraction form
    28,239/38,970 = 15,663.78/x
  3. Step 3: Cross multiply
    28,239x = 38,970 × 15,663.78
  4. Step 4: Simplify right side
    28,239x = 610,417,506.60
  5. Step 5: Solve for x
    x = 610,417,506.60/28,239
  6. Step 6: Final answer
    x = 21,616.12

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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.