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Finding the Fourth Proportional to 989.40, 1,484 and 258.88

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Solution

The fourth proportional to 989.40, 1,484 and 258.88 is: 388.29

Step by Step Solution

  1. Step 1: Write the proportion equation
    989.40 : 1,484 = 258.88 : x
  2. Step 2: Convert to fraction form
    989.40/1,484 = 258.88/x
  3. Step 3: Cross multiply
    989.40x = 1,484 × 258.88
  4. Step 4: Simplify right side
    989.40x = 384,177.92
  5. Step 5: Solve for x
    x = 384,177.92/989.40
  6. Step 6: Final answer
    x = 388.29

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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.