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Finding the Fourth Proportional to 390.29, 538.74 and 307.77

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Solution

The fourth proportional to 390.29, 538.74 and 307.77 is: 424.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.29 : 538.74 = 307.77 : x
  2. Step 2: Convert to fraction form
    390.29/538.74 = 307.77/x
  3. Step 3: Cross multiply
    390.29x = 538.74 × 307.77
  4. Step 4: Simplify right side
    390.29x = 165,808.01
  5. Step 5: Solve for x
    x = 165,808.01/390.29
  6. Step 6: Final answer
    x = 424.83

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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.