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Finding the Fourth Proportional to 990.14, 1,486.80 and 579.60

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Solution

The fourth proportional to 990.14, 1,486.80 and 579.60 is: 870.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    990.14 : 1,486.80 = 579.60 : x
  2. Step 2: Convert to fraction form
    990.14/1,486.80 = 579.60/x
  3. Step 3: Cross multiply
    990.14x = 1,486.80 × 579.60
  4. Step 4: Simplify right side
    990.14x = 861,749.28
  5. Step 5: Solve for x
    x = 861,749.28/990.14
  6. Step 6: Final answer
    x = 870.34

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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.