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Finding the Fourth Proportional to 631.68, 870.86 and 421.89

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Solution

The fourth proportional to 631.68, 870.86 and 421.89 is: 581.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    631.68 : 870.86 = 421.89 : x
  2. Step 2: Convert to fraction form
    631.68/870.86 = 421.89/x
  3. Step 3: Cross multiply
    631.68x = 870.86 × 421.89
  4. Step 4: Simplify right side
    631.68x = 367,405.02
  5. Step 5: Solve for x
    x = 367,405.02/631.68
  6. Step 6: Final answer
    x = 581.63

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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.