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Finding the Fourth Proportional to 772.56, 1,156.32 and 420.64

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Solution

The fourth proportional to 772.56, 1,156.32 and 420.64 is: 629.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    772.56 : 1,156.32 = 420.64 : x
  2. Step 2: Convert to fraction form
    772.56/1,156.32 = 420.64/x
  3. Step 3: Cross multiply
    772.56x = 1,156.32 × 420.64
  4. Step 4: Simplify right side
    772.56x = 486,391.55
  5. Step 5: Solve for x
    x = 486,391.55/772.56
  6. Step 6: Final answer
    x = 629.58

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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.