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Finding the Fourth Proportional to 390.79, 586.25 and 130.78

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Solution

The fourth proportional to 390.79, 586.25 and 130.78 is: 196.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.79 : 586.25 = 130.78 : x
  2. Step 2: Convert to fraction form
    390.79/586.25 = 130.78/x
  3. Step 3: Cross multiply
    390.79x = 586.25 × 130.78
  4. Step 4: Simplify right side
    390.79x = 76,669.78
  5. Step 5: Solve for x
    x = 76,669.78/390.79
  6. Step 6: Final answer
    x = 196.19

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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.