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Finding the Fourth Proportional to 390.12, 585.40 and 146.72

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Solution

The fourth proportional to 390.12, 585.40 and 146.72 is: 220.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.12 : 585.40 = 146.72 : x
  2. Step 2: Convert to fraction form
    390.12/585.40 = 146.72/x
  3. Step 3: Cross multiply
    390.12x = 585.40 × 146.72
  4. Step 4: Simplify right side
    390.12x = 85,889.89
  5. Step 5: Solve for x
    x = 85,889.89/390.12
  6. Step 6: Final answer
    x = 220.16

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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.