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Finding the Fourth Proportional to 678.25, 1,017.43 and 385.64

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Solution

The fourth proportional to 678.25, 1,017.43 and 385.64 is: 578.49

Step by Step Solution

  1. Step 1: Write the proportion equation
    678.25 : 1,017.43 = 385.64 : x
  2. Step 2: Convert to fraction form
    678.25/1,017.43 = 385.64/x
  3. Step 3: Cross multiply
    678.25x = 1,017.43 × 385.64
  4. Step 4: Simplify right side
    678.25x = 392,361.71
  5. Step 5: Solve for x
    x = 392,361.71/678.25
  6. Step 6: Final answer
    x = 578.49

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1.5x scale

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.