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Finding the Fourth Proportional to 507.40, 762.80 and 405.79

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Solution

The fourth proportional to 507.40, 762.80 and 405.79 is: 610.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    507.40 : 762.80 = 405.79 : x
  2. Step 2: Convert to fraction form
    507.40/762.80 = 405.79/x
  3. Step 3: Cross multiply
    507.40x = 762.80 × 405.79
  4. Step 4: Simplify right side
    507.40x = 309,539.25
  5. Step 5: Solve for x
    x = 309,539.25/507.40
  6. Step 6: Final answer
    x = 610.05

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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.