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Finding the Fourth Proportional to 390, 585.45 and 216.84

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Solution

The fourth proportional to 390, 585.45 and 216.84 is: 325.51

Step by Step Solution

  1. Step 1: Write the proportion equation
    390 : 585.45 = 216.84 : x
  2. Step 2: Convert to fraction form
    390/585.45 = 216.84/x
  3. Step 3: Cross multiply
    390x = 585.45 × 216.84
  4. Step 4: Simplify right side
    390x = 126,948.98
  5. Step 5: Solve for x
    x = 126,948.98/390
  6. Step 6: Final answer
    x = 325.51

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.