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Finding the Fourth Proportional to 631.48, 870.66 and 398.20

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Solution

The fourth proportional to 631.48, 870.66 and 398.20 is: 549.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    631.48 : 870.66 = 398.20 : x
  2. Step 2: Convert to fraction form
    631.48/870.66 = 398.20/x
  3. Step 3: Cross multiply
    631.48x = 870.66 × 398.20
  4. Step 4: Simplify right side
    631.48x = 346,696.81
  5. Step 5: Solve for x
    x = 346,696.81/631.48
  6. Step 6: Final answer
    x = 549.02

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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.