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Finding the Fourth Proportional to 631.12, 870.72 and 398.08

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Solution

The fourth proportional to 631.12, 870.72 and 398.08 is: 549.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    631.12 : 870.72 = 398.08 : x
  2. Step 2: Convert to fraction form
    631.12/870.72 = 398.08/x
  3. Step 3: Cross multiply
    631.12x = 870.72 × 398.08
  4. Step 4: Simplify right side
    631.12x = 346,616.22
  5. Step 5: Solve for x
    x = 346,616.22/631.12
  6. Step 6: Final answer
    x = 549.21

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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.