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Finding the Fourth Proportional to 989.99, 1,485.04 and 442.21

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Solution

The fourth proportional to 989.99, 1,485.04 and 442.21 is: 663.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    989.99 : 1,485.04 = 442.21 : x
  2. Step 2: Convert to fraction form
    989.99/1,485.04 = 442.21/x
  3. Step 3: Cross multiply
    989.99x = 1,485.04 × 442.21
  4. Step 4: Simplify right side
    989.99x = 656,699.54
  5. Step 5: Solve for x
    x = 656,699.54/989.99
  6. Step 6: Final answer
    x = 663.34

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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.