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Finding the Fourth Proportional to 663.84, 996 and 390

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Solution

The fourth proportional to 663.84, 996 and 390 is: 585.14

Step by Step Solution

  1. Step 1: Write the proportion equation
    663.84 : 996 = 390 : x
  2. Step 2: Convert to fraction form
    663.84/996 = 390/x
  3. Step 3: Cross multiply
    663.84x = 996 × 390
  4. Step 4: Simplify right side
    663.84x = 388,440
  5. Step 5: Solve for x
    x = 388,440/663.84
  6. Step 6: Final answer
    x = 585.14

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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.