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Finding the Fourth Proportional to 631.10, 870.90 and 398

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Solution

The fourth proportional to 631.10, 870.90 and 398 is: 549.23

Step by Step Solution

  1. Step 1: Write the proportion equation
    631.10 : 870.90 = 398 : x
  2. Step 2: Convert to fraction form
    631.10/870.90 = 398/x
  3. Step 3: Cross multiply
    631.10x = 870.90 × 398
  4. Step 4: Simplify right side
    631.10x = 346,618.20
  5. Step 5: Solve for x
    x = 346,618.20/631.10
  6. Step 6: Final answer
    x = 549.23

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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.