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Finding the Fourth Proportional to 390.85, 539.16 and 258.11

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Solution

The fourth proportional to 390.85, 539.16 and 258.11 is: 356.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.85 : 539.16 = 258.11 : x
  2. Step 2: Convert to fraction form
    390.85/539.16 = 258.11/x
  3. Step 3: Cross multiply
    390.85x = 539.16 × 258.11
  4. Step 4: Simplify right side
    390.85x = 139,162.46
  5. Step 5: Solve for x
    x = 139,162.46/390.85
  6. Step 6: Final answer
    x = 356.05

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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.