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Finding the Fourth Proportional to 455.12, 628.40 and 280.70

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Solution

The fourth proportional to 455.12, 628.40 and 280.70 is: 387.57

Step by Step Solution

  1. Step 1: Write the proportion equation
    455.12 : 628.40 = 280.70 : x
  2. Step 2: Convert to fraction form
    455.12/628.40 = 280.70/x
  3. Step 3: Cross multiply
    455.12x = 628.40 × 280.70
  4. Step 4: Simplify right side
    455.12x = 176,391.88
  5. Step 5: Solve for x
    x = 176,391.88/455.12
  6. Step 6: Final answer
    x = 387.57

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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.