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Finding the Fourth Proportional to 689.90, 951.78 and 395

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Solution

The fourth proportional to 689.90, 951.78 and 395 is: 544.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    689.90 : 951.78 = 395 : x
  2. Step 2: Convert to fraction form
    689.90/951.78 = 395/x
  3. Step 3: Cross multiply
    689.90x = 951.78 × 395
  4. Step 4: Simplify right side
    689.90x = 375,953.10
  5. Step 5: Solve for x
    x = 375,953.10/689.90
  6. Step 6: Final answer
    x = 544.94

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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.