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Finding the Fourth Proportional to 428.49, 587.45 and 420.70

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Solution

The fourth proportional to 428.49, 587.45 and 420.70 is: 576.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.49 : 587.45 = 420.70 : x
  2. Step 2: Convert to fraction form
    428.49/587.45 = 420.70/x
  3. Step 3: Cross multiply
    428.49x = 587.45 × 420.70
  4. Step 4: Simplify right side
    428.49x = 247,140.22
  5. Step 5: Solve for x
    x = 247,140.22/428.49
  6. Step 6: Final answer
    x = 576.78

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Why These Related Problems?

These problems maintain the same ratio (1.37) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.