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Finding the Fourth Proportional to 409.65, 612.64 and 390.81

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Solution

The fourth proportional to 409.65, 612.64 and 390.81 is: 584.46

Step by Step Solution

  1. Step 1: Write the proportion equation
    409.65 : 612.64 = 390.81 : x
  2. Step 2: Convert to fraction form
    409.65/612.64 = 390.81/x
  3. Step 3: Cross multiply
    409.65x = 612.64 × 390.81
  4. Step 4: Simplify right side
    409.65x = 239,425.84
  5. Step 5: Solve for x
    x = 239,425.84/409.65
  6. Step 6: Final answer
    x = 584.46

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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.