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Finding the Fourth Proportional to 678.16, 935.80 and 398.35

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Solution

The fourth proportional to 678.16, 935.80 and 398.35 is: 549.69

Step by Step Solution

  1. Step 1: Write the proportion equation
    678.16 : 935.80 = 398.35 : x
  2. Step 2: Convert to fraction form
    678.16/935.80 = 398.35/x
  3. Step 3: Cross multiply
    678.16x = 935.80 × 398.35
  4. Step 4: Simplify right side
    678.16x = 372,775.93
  5. Step 5: Solve for x
    x = 372,775.93/678.16
  6. Step 6: Final answer
    x = 549.69

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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.