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Finding the Fourth Proportional to 663.80, 915.90 and 398.16

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Solution

The fourth proportional to 663.80, 915.90 and 398.16 is: 549.37

Step by Step Solution

  1. Step 1: Write the proportion equation
    663.80 : 915.90 = 398.16 : x
  2. Step 2: Convert to fraction form
    663.80/915.90 = 398.16/x
  3. Step 3: Cross multiply
    663.80x = 915.90 × 398.16
  4. Step 4: Simplify right side
    663.80x = 364,674.74
  5. Step 5: Solve for x
    x = 364,674.74/663.80
  6. Step 6: Final answer
    x = 549.37

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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.