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Finding the Fourth Proportional to 21,000, 28,980 and 11,568.77

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Solution

The fourth proportional to 21,000, 28,980 and 11,568.77 is: 15,964.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    21,000 : 28,980 = 11,568.77 : x
  2. Step 2: Convert to fraction form
    21,000/28,980 = 11,568.77/x
  3. Step 3: Cross multiply
    21,000x = 28,980 × 11,568.77
  4. Step 4: Simplify right side
    21,000x = 335,262,809.70
  5. Step 5: Solve for x
    x = 335,262,809.70/21,000
  6. Step 6: Final answer
    x = 15,964.90

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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.