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Finding the Fourth Proportional to 680.64, 939.32 and 400.81

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Solution

The fourth proportional to 680.64, 939.32 and 400.81 is: 553.13

Step by Step Solution

  1. Step 1: Write the proportion equation
    680.64 : 939.32 = 400.81 : x
  2. Step 2: Convert to fraction form
    680.64/939.32 = 400.81/x
  3. Step 3: Cross multiply
    680.64x = 939.32 × 400.81
  4. Step 4: Simplify right side
    680.64x = 376,482.15
  5. Step 5: Solve for x
    x = 376,482.15/680.64
  6. Step 6: Final answer
    x = 553.13

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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.