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Finding the Fourth Proportional to 989.78, 1,484.69 and 259.43

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Solution

The fourth proportional to 989.78, 1,484.69 and 259.43 is: 389.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    989.78 : 1,484.69 = 259.43 : x
  2. Step 2: Convert to fraction form
    989.78/1,484.69 = 259.43/x
  3. Step 3: Cross multiply
    989.78x = 1,484.69 × 259.43
  4. Step 4: Simplify right side
    989.78x = 385,164.41
  5. Step 5: Solve for x
    x = 385,164.41/989.78
  6. Step 6: Final answer
    x = 389.14

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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.