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Finding the Fourth Proportional to 708.70, 977.97 and 398.20

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Solution

The fourth proportional to 708.70, 977.97 and 398.20 is: 549.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    708.70 : 977.97 = 398.20 : x
  2. Step 2: Convert to fraction form
    708.70/977.97 = 398.20/x
  3. Step 3: Cross multiply
    708.70x = 977.97 × 398.20
  4. Step 4: Simplify right side
    708.70x = 389,427.65
  5. Step 5: Solve for x
    x = 389,427.65/708.70
  6. Step 6: Final answer
    x = 549.50

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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.