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Finding the Fourth Proportional to 678.10, 1,015.30 and 352.78

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Solution

The fourth proportional to 678.10, 1,015.30 and 352.78 is: 528.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    678.10 : 1,015.30 = 352.78 : x
  2. Step 2: Convert to fraction form
    678.10/1,015.30 = 352.78/x
  3. Step 3: Cross multiply
    678.10x = 1,015.30 × 352.78
  4. Step 4: Simplify right side
    678.10x = 358,177.53
  5. Step 5: Solve for x
    x = 358,177.53/678.10
  6. Step 6: Final answer
    x = 528.21

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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.