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Finding the Fourth Proportional to 680.39, 938.90 and 385.64

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Solution

The fourth proportional to 680.39, 938.90 and 385.64 is: 532.16

Step by Step Solution

  1. Step 1: Write the proportion equation
    680.39 : 938.90 = 385.64 : x
  2. Step 2: Convert to fraction form
    680.39/938.90 = 385.64/x
  3. Step 3: Cross multiply
    680.39x = 938.90 × 385.64
  4. Step 4: Simplify right side
    680.39x = 362,070.77
  5. Step 5: Solve for x
    x = 362,070.77/680.39
  6. Step 6: Final answer
    x = 532.16

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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.