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Finding the Fourth Proportional to 390.70, 586.45 and 208.25

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Solution

The fourth proportional to 390.70, 586.45 and 208.25 is: 312.59

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.70 : 586.45 = 208.25 : x
  2. Step 2: Convert to fraction form
    390.70/586.45 = 208.25/x
  3. Step 3: Cross multiply
    390.70x = 586.45 × 208.25
  4. Step 4: Simplify right side
    390.70x = 122,128.21
  5. Step 5: Solve for x
    x = 122,128.21/390.70
  6. Step 6: Final answer
    x = 312.59

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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.