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Finding the Fourth Proportional to 390.45, 585.78 and 147.05

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Solution

The fourth proportional to 390.45, 585.78 and 147.05 is: 220.61

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.45 : 585.78 = 147.05 : x
  2. Step 2: Convert to fraction form
    390.45/585.78 = 147.05/x
  3. Step 3: Cross multiply
    390.45x = 585.78 × 147.05
  4. Step 4: Simplify right side
    390.45x = 86,138.49
  5. Step 5: Solve for x
    x = 86,138.49/390.45
  6. Step 6: Final answer
    x = 220.61

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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.