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Finding the Fourth Proportional to 921.81, 1,272.11 and 507.81

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Solution

The fourth proportional to 921.81, 1,272.11 and 507.81 is: 700.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    921.81 : 1,272.11 = 507.81 : x
  2. Step 2: Convert to fraction form
    921.81/1,272.11 = 507.81/x
  3. Step 3: Cross multiply
    921.81x = 1,272.11 × 507.81
  4. Step 4: Simplify right side
    921.81x = 645,990.18
  5. Step 5: Solve for x
    x = 645,990.18/921.81
  6. Step 6: Final answer
    x = 700.78

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.