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Finding the Fourth Proportional to 665.63, 997.79 and 391.35

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Solution

The fourth proportional to 665.63, 997.79 and 391.35 is: 586.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    665.63 : 997.79 = 391.35 : x
  2. Step 2: Convert to fraction form
    665.63/997.79 = 391.35/x
  3. Step 3: Cross multiply
    665.63x = 997.79 × 391.35
  4. Step 4: Simplify right side
    665.63x = 390,483.16
  5. Step 5: Solve for x
    x = 390,483.16/665.63
  6. Step 6: Final answer
    x = 586.64

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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.