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Finding the Fourth Proportional to 390.63, 587 and 208.11

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Solution

The fourth proportional to 390.63, 587 and 208.11 is: 312.73

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.63 : 587 = 208.11 : x
  2. Step 2: Convert to fraction form
    390.63/587 = 208.11/x
  3. Step 3: Cross multiply
    390.63x = 587 × 208.11
  4. Step 4: Simplify right side
    390.63x = 122,160.57
  5. Step 5: Solve for x
    x = 122,160.57/390.63
  6. Step 6: Final answer
    x = 312.73

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.