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Finding the Fourth Proportional to 708.80, 978.06 and 398.28

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Solution

The fourth proportional to 708.80, 978.06 and 398.28 is: 549.58

Step by Step Solution

  1. Step 1: Write the proportion equation
    708.80 : 978.06 = 398.28 : x
  2. Step 2: Convert to fraction form
    708.80/978.06 = 398.28/x
  3. Step 3: Cross multiply
    708.80x = 978.06 × 398.28
  4. Step 4: Simplify right side
    708.80x = 389,541.74
  5. Step 5: Solve for x
    x = 389,541.74/708.80
  6. Step 6: Final answer
    x = 549.58

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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.