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Finding the Fourth Proportional to 989.68, 1,484.65 and 638.56

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Solution

The fourth proportional to 989.68, 1,484.65 and 638.56 is: 957.92

Step by Step Solution

  1. Step 1: Write the proportion equation
    989.68 : 1,484.65 = 638.56 : x
  2. Step 2: Convert to fraction form
    989.68/1,484.65 = 638.56/x
  3. Step 3: Cross multiply
    989.68x = 1,484.65 × 638.56
  4. Step 4: Simplify right side
    989.68x = 948,034.91
  5. Step 5: Solve for x
    x = 948,034.91/989.68
  6. Step 6: Final answer
    x = 957.92

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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.