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Finding the Fourth Proportional to 390.39, 538.95 and 307.77

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Solution

The fourth proportional to 390.39, 538.95 and 307.77 is: 424.89

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.39 : 538.95 = 307.77 : x
  2. Step 2: Convert to fraction form
    390.39/538.95 = 307.77/x
  3. Step 3: Cross multiply
    390.39x = 538.95 × 307.77
  4. Step 4: Simplify right side
    390.39x = 165,872.64
  5. Step 5: Solve for x
    x = 165,872.64/390.39
  6. Step 6: Final answer
    x = 424.89

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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.