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Finding the Fourth Proportional to 856.77, 1,278.30 and 764.43

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Solution

The fourth proportional to 856.77, 1,278.30 and 764.43 is: 1,140.53

Step by Step Solution

  1. Step 1: Write the proportion equation
    856.77 : 1,278.30 = 764.43 : x
  2. Step 2: Convert to fraction form
    856.77/1,278.30 = 764.43/x
  3. Step 3: Cross multiply
    856.77x = 1,278.30 × 764.43
  4. Step 4: Simplify right side
    856.77x = 977,170.87
  5. Step 5: Solve for x
    x = 977,170.87/856.77
  6. Step 6: Final answer
    x = 1,140.53

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.