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Finding the Fourth Proportional to 18,720, 28,080 and 4,869

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Solution

The fourth proportional to 18,720, 28,080 and 4,869 is: 7,303.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    18,720 : 28,080 = 4,869 : x
  2. Step 2: Convert to fraction form
    18,720/28,080 = 4,869/x
  3. Step 3: Cross multiply
    18,720x = 28,080 × 4,869
  4. Step 4: Simplify right side
    18,720x = 136,721,520
  5. Step 5: Solve for x
    x = 136,721,520/18,720
  6. Step 6: Final answer
    x = 7,303.50

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Why These Related Problems?

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