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Finding the Fourth Proportional to 990.60, 1,485.88 and 405.84

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Solution

The fourth proportional to 990.60, 1,485.88 and 405.84 is: 608.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    990.60 : 1,485.88 = 405.84 : x
  2. Step 2: Convert to fraction form
    990.60/1,485.88 = 405.84/x
  3. Step 3: Cross multiply
    990.60x = 1,485.88 × 405.84
  4. Step 4: Simplify right side
    990.60x = 603,029.54
  5. Step 5: Solve for x
    x = 603,029.54/990.60
  6. Step 6: Final answer
    x = 608.75

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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.