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Finding the Fourth Proportional to 665.19, 999.21 and 643.32

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Solution

The fourth proportional to 665.19, 999.21 and 643.32 is: 966.36

Step by Step Solution

  1. Step 1: Write the proportion equation
    665.19 : 999.21 = 643.32 : x
  2. Step 2: Convert to fraction form
    665.19/999.21 = 643.32/x
  3. Step 3: Cross multiply
    665.19x = 999.21 × 643.32
  4. Step 4: Simplify right side
    665.19x = 642,811.78
  5. Step 5: Solve for x
    x = 642,811.78/665.19
  6. Step 6: Final answer
    x = 966.36

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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.