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Finding the Fourth Proportional to 427.68, 640.80 and 342

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Solution

The fourth proportional to 427.68, 640.80 and 342 is: 512.42

Step by Step Solution

  1. Step 1: Write the proportion equation
    427.68 : 640.80 = 342 : x
  2. Step 2: Convert to fraction form
    427.68/640.80 = 342/x
  3. Step 3: Cross multiply
    427.68x = 640.80 × 342
  4. Step 4: Simplify right side
    427.68x = 219,153.60
  5. Step 5: Solve for x
    x = 219,153.60/427.68
  6. Step 6: Final answer
    x = 512.42

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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.