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Finding the Fourth Proportional to 708.55, 977.78 and 393.80

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Solution

The fourth proportional to 708.55, 977.78 and 393.80 is: 543.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    708.55 : 977.78 = 393.80 : x
  2. Step 2: Convert to fraction form
    708.55/977.78 = 393.80/x
  3. Step 3: Cross multiply
    708.55x = 977.78 × 393.80
  4. Step 4: Simplify right side
    708.55x = 385,045.86
  5. Step 5: Solve for x
    x = 385,045.86/708.55
  6. Step 6: Final answer
    x = 543.43

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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.