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Finding the Fourth Proportional to 505.40, 698.16 and 390.44

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Solution

The fourth proportional to 505.40, 698.16 and 390.44 is: 539.35

Step by Step Solution

  1. Step 1: Write the proportion equation
    505.40 : 698.16 = 390.44 : x
  2. Step 2: Convert to fraction form
    505.40/698.16 = 390.44/x
  3. Step 3: Cross multiply
    505.40x = 698.16 × 390.44
  4. Step 4: Simplify right side
    505.40x = 272,589.59
  5. Step 5: Solve for x
    x = 272,589.59/505.40
  6. Step 6: Final answer
    x = 539.35

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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.