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Finding the Fourth Proportional to 772.86, 1,156.70 and 420.98

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Solution

The fourth proportional to 772.86, 1,156.70 and 420.98 is: 630.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    772.86 : 1,156.70 = 420.98 : x
  2. Step 2: Convert to fraction form
    772.86/1,156.70 = 420.98/x
  3. Step 3: Cross multiply
    772.86x = 1,156.70 × 420.98
  4. Step 4: Simplify right side
    772.86x = 486,939.68
  5. Step 5: Solve for x
    x = 486,939.68/772.86
  6. Step 6: Final answer
    x = 630.05

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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.