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Finding the Fourth Proportional to 421.26, 581.52 and 390.60

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Solution

The fourth proportional to 421.26, 581.52 and 390.60 is: 539.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.26 : 581.52 = 390.60 : x
  2. Step 2: Convert to fraction form
    421.26/581.52 = 390.60/x
  3. Step 3: Cross multiply
    421.26x = 581.52 × 390.60
  4. Step 4: Simplify right side
    421.26x = 227,141.71
  5. Step 5: Solve for x
    x = 227,141.71/421.26
  6. Step 6: Final answer
    x = 539.20

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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.