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Finding the Fourth Proportional to 505.78, 697.74 and 309.34

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Solution

The fourth proportional to 505.78, 697.74 and 309.34 is: 426.74

Step by Step Solution

  1. Step 1: Write the proportion equation
    505.78 : 697.74 = 309.34 : x
  2. Step 2: Convert to fraction form
    505.78/697.74 = 309.34/x
  3. Step 3: Cross multiply
    505.78x = 697.74 × 309.34
  4. Step 4: Simplify right side
    505.78x = 215,838.89
  5. Step 5: Solve for x
    x = 215,838.89/505.78
  6. Step 6: Final answer
    x = 426.74

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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.