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Finding the Fourth Proportional to 390.78, 585.23 and 298.78

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Solution

The fourth proportional to 390.78, 585.23 and 298.78 is: 447.44

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.78 : 585.23 = 298.78 : x
  2. Step 2: Convert to fraction form
    390.78/585.23 = 298.78/x
  3. Step 3: Cross multiply
    390.78x = 585.23 × 298.78
  4. Step 4: Simplify right side
    390.78x = 174,852.06
  5. Step 5: Solve for x
    x = 174,852.06/390.78
  6. Step 6: Final answer
    x = 447.44

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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.