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Finding the Fourth Proportional to 678.19, 1,017.26 and 312.97

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Solution

The fourth proportional to 678.19, 1,017.26 and 312.97 is: 469.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    678.19 : 1,017.26 = 312.97 : x
  2. Step 2: Convert to fraction form
    678.19/1,017.26 = 312.97/x
  3. Step 3: Cross multiply
    678.19x = 1,017.26 × 312.97
  4. Step 4: Simplify right side
    678.19x = 318,374.36
  5. Step 5: Solve for x
    x = 318,374.36/678.19
  6. Step 6: Final answer
    x = 469.45

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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.