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Finding the Fourth Proportional to 421.72, 581.70 and 247

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Solution

The fourth proportional to 421.72, 581.70 and 247 is: 340.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.72 : 581.70 = 247 : x
  2. Step 2: Convert to fraction form
    421.72/581.70 = 247/x
  3. Step 3: Cross multiply
    421.72x = 581.70 × 247
  4. Step 4: Simplify right side
    421.72x = 143,679.90
  5. Step 5: Solve for x
    x = 143,679.90/421.72
  6. Step 6: Final answer
    x = 340.70

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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.