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Finding the Fourth Proportional to 390.60, 538.74 and 307.56

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Solution

The fourth proportional to 390.60, 538.74 and 307.56 is: 424.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.60 : 538.74 = 307.56 : x
  2. Step 2: Convert to fraction form
    390.60/538.74 = 307.56/x
  3. Step 3: Cross multiply
    390.60x = 538.74 × 307.56
  4. Step 4: Simplify right side
    390.60x = 165,694.87
  5. Step 5: Solve for x
    x = 165,694.87/390.60
  6. Step 6: Final answer
    x = 424.21

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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.