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Finding the Fourth Proportional to 708.84, 978.21 and 398.34

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Solution

The fourth proportional to 708.84, 978.21 and 398.34 is: 549.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    708.84 : 978.21 = 398.34 : x
  2. Step 2: Convert to fraction form
    708.84/978.21 = 398.34/x
  3. Step 3: Cross multiply
    708.84x = 978.21 × 398.34
  4. Step 4: Simplify right side
    708.84x = 389,660.17
  5. Step 5: Solve for x
    x = 389,660.17/708.84
  6. Step 6: Final answer
    x = 549.72

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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.