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Finding the Fourth Proportional to 990.45, 1,484.78 and 405.32

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Solution

The fourth proportional to 990.45, 1,484.78 and 405.32 is: 607.60

Step by Step Solution

  1. Step 1: Write the proportion equation
    990.45 : 1,484.78 = 405.32 : x
  2. Step 2: Convert to fraction form
    990.45/1,484.78 = 405.32/x
  3. Step 3: Cross multiply
    990.45x = 1,484.78 × 405.32
  4. Step 4: Simplify right side
    990.45x = 601,801.58
  5. Step 5: Solve for x
    x = 601,801.58/990.45
  6. Step 6: Final answer
    x = 607.60

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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.