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Finding the Fourth Proportional to 678.82, 1,017.69 and 313.42

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Solution

The fourth proportional to 678.82, 1,017.69 and 313.42 is: 469.88

Step by Step Solution

  1. Step 1: Write the proportion equation
    678.82 : 1,017.69 = 313.42 : x
  2. Step 2: Convert to fraction form
    678.82/1,017.69 = 313.42/x
  3. Step 3: Cross multiply
    678.82x = 1,017.69 × 313.42
  4. Step 4: Simplify right side
    678.82x = 318,964.40
  5. Step 5: Solve for x
    x = 318,964.40/678.82
  6. Step 6: Final answer
    x = 469.88

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.