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Finding the Fourth Proportional to 421.19, 631.80 and 387.36

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Solution

The fourth proportional to 421.19, 631.80 and 387.36 is: 581.05

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.19 : 631.80 = 387.36 : x
  2. Step 2: Convert to fraction form
    421.19/631.80 = 387.36/x
  3. Step 3: Cross multiply
    421.19x = 631.80 × 387.36
  4. Step 4: Simplify right side
    421.19x = 244,734.05
  5. Step 5: Solve for x
    x = 244,734.05/421.19
  6. Step 6: Final answer
    x = 581.05

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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.