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Finding the Fourth Proportional to 390.64, 539.10 and 215.98

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Solution

The fourth proportional to 390.64, 539.10 and 215.98 is: 298.06

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.64 : 539.10 = 215.98 : x
  2. Step 2: Convert to fraction form
    390.64/539.10 = 215.98/x
  3. Step 3: Cross multiply
    390.64x = 539.10 × 215.98
  4. Step 4: Simplify right side
    390.64x = 116,434.82
  5. Step 5: Solve for x
    x = 116,434.82/390.64
  6. Step 6: Final answer
    x = 298.06

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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.