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Finding the Fourth Proportional to 8,145, 12,217.50 and 1,989

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Solution

The fourth proportional to 8,145, 12,217.50 and 1,989 is: 2,983.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    8,145 : 12,217.50 = 1,989 : x
  2. Step 2: Convert to fraction form
    8,145/12,217.50 = 1,989/x
  3. Step 3: Cross multiply
    8,145x = 12,217.50 × 1,989
  4. Step 4: Simplify right side
    8,145x = 24,300,607.50
  5. Step 5: Solve for x
    x = 24,300,607.50/8,145
  6. Step 6: Final answer
    x = 2,983.50

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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.