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Finding the Fourth Proportional to 663.60, 915.81 and 398.05

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Solution

The fourth proportional to 663.60, 915.81 and 398.05 is: 549.34

Step by Step Solution

  1. Step 1: Write the proportion equation
    663.60 : 915.81 = 398.05 : x
  2. Step 2: Convert to fraction form
    663.60/915.81 = 398.05/x
  3. Step 3: Cross multiply
    663.60x = 915.81 × 398.05
  4. Step 4: Simplify right side
    663.60x = 364,536.57
  5. Step 5: Solve for x
    x = 364,536.57/663.60
  6. Step 6: Final answer
    x = 549.34

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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.