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Finding the Fourth Proportional to 1,221.15, 1,830.71 and 989.47

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Solution

The fourth proportional to 1,221.15, 1,830.71 and 989.47 is: 1,483.37

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,221.15 : 1,830.71 = 989.47 : x
  2. Step 2: Convert to fraction form
    1,221.15/1,830.71 = 989.47/x
  3. Step 3: Cross multiply
    1,221.15x = 1,830.71 × 989.47
  4. Step 4: Simplify right side
    1,221.15x = 1,811,423.10
  5. Step 5: Solve for x
    x = 1,811,423.10/1,221.15
  6. Step 6: Final answer
    x = 1,483.37

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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.