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Finding the Fourth Proportional to 663.78, 915.76 and 401.70

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Solution

The fourth proportional to 663.78, 915.76 and 401.70 is: 554.19

Step by Step Solution

  1. Step 1: Write the proportion equation
    663.78 : 915.76 = 401.70 : x
  2. Step 2: Convert to fraction form
    663.78/915.76 = 401.70/x
  3. Step 3: Cross multiply
    663.78x = 915.76 × 401.70
  4. Step 4: Simplify right side
    663.78x = 367,860.79
  5. Step 5: Solve for x
    x = 367,860.79/663.78
  6. Step 6: Final answer
    x = 554.19

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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.