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Finding the Fourth Proportional to 678.20, 935.80 and 383.40

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Solution

The fourth proportional to 678.20, 935.80 and 383.40 is: 529.03

Step by Step Solution

  1. Step 1: Write the proportion equation
    678.20 : 935.80 = 383.40 : x
  2. Step 2: Convert to fraction form
    678.20/935.80 = 383.40/x
  3. Step 3: Cross multiply
    678.20x = 935.80 × 383.40
  4. Step 4: Simplify right side
    678.20x = 358,784.76
  5. Step 5: Solve for x
    x = 358,784.76/678.20
  6. Step 6: Final answer
    x = 529.03

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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.