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Finding the Fourth Proportional to 390.94, 539.51 and 216.30

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Solution

The fourth proportional to 390.94, 539.51 and 216.30 is: 298.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    390.94 : 539.51 = 216.30 : x
  2. Step 2: Convert to fraction form
    390.94/539.51 = 216.30/x
  3. Step 3: Cross multiply
    390.94x = 539.51 × 216.30
  4. Step 4: Simplify right side
    390.94x = 116,692.23
  5. Step 5: Solve for x
    x = 116,692.23/390.94
  6. Step 6: Final answer
    x = 298.49

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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.