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Finding the Fourth Proportional to 565.56, 780 and 390.90

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Solution

The fourth proportional to 565.56, 780 and 390.90 is: 539.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    565.56 : 780 = 390.90 : x
  2. Step 2: Convert to fraction form
    565.56/780 = 390.90/x
  3. Step 3: Cross multiply
    565.56x = 780 × 390.90
  4. Step 4: Simplify right side
    565.56x = 304,902
  5. Step 5: Solve for x
    x = 304,902/565.56
  6. Step 6: Final answer
    x = 539.12

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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.