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Finding the Fourth Proportional to 989.87, 1,485.17 and 340.65

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Solution

The fourth proportional to 989.87, 1,485.17 and 340.65 is: 511.10

Step by Step Solution

  1. Step 1: Write the proportion equation
    989.87 : 1,485.17 = 340.65 : x
  2. Step 2: Convert to fraction form
    989.87/1,485.17 = 340.65/x
  3. Step 3: Cross multiply
    989.87x = 1,485.17 × 340.65
  4. Step 4: Simplify right side
    989.87x = 505,921.46
  5. Step 5: Solve for x
    x = 505,921.46/989.87
  6. Step 6: Final answer
    x = 511.10

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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.