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Finding the Fourth Proportional to 900.78, 1,243.11 and 507.78

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Solution

The fourth proportional to 900.78, 1,243.11 and 507.78 is: 700.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    900.78 : 1,243.11 = 507.78 : x
  2. Step 2: Convert to fraction form
    900.78/1,243.11 = 507.78/x
  3. Step 3: Cross multiply
    900.78x = 1,243.11 × 507.78
  4. Step 4: Simplify right side
    900.78x = 631,226.40
  5. Step 5: Solve for x
    x = 631,226.40/900.78
  6. Step 6: Final answer
    x = 700.76

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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.