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Finding the Fourth Proportional to 421.65, 581.58 and 255.78

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Solution

The fourth proportional to 421.65, 581.58 and 255.78 is: 352.80

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.65 : 581.58 = 255.78 : x
  2. Step 2: Convert to fraction form
    421.65/581.58 = 255.78/x
  3. Step 3: Cross multiply
    421.65x = 581.58 × 255.78
  4. Step 4: Simplify right side
    421.65x = 148,756.53
  5. Step 5: Solve for x
    x = 148,756.53/421.65
  6. Step 6: Final answer
    x = 352.80

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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.