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Finding the Fourth Proportional to 420.48, 579.60 and 309.60

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Solution

The fourth proportional to 420.48, 579.60 and 309.60 is: 426.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.48 : 579.60 = 309.60 : x
  2. Step 2: Convert to fraction form
    420.48/579.60 = 309.60/x
  3. Step 3: Cross multiply
    420.48x = 579.60 × 309.60
  4. Step 4: Simplify right side
    420.48x = 179,444.16
  5. Step 5: Solve for x
    x = 179,444.16/420.48
  6. Step 6: Final answer
    x = 426.76

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.