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Finding the Fourth Proportional to 421.86, 631.86 and 259.06

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Solution

The fourth proportional to 421.86, 631.86 and 259.06 is: 388.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.86 : 631.86 = 259.06 : x
  2. Step 2: Convert to fraction form
    421.86/631.86 = 259.06/x
  3. Step 3: Cross multiply
    421.86x = 631.86 × 259.06
  4. Step 4: Simplify right side
    421.86x = 163,689.65
  5. Step 5: Solve for x
    x = 163,689.65/421.86
  6. Step 6: Final answer
    x = 388.02

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.