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Finding the Fourth Proportional to 421.58, 632.15 and 129

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Solution

The fourth proportional to 421.58, 632.15 and 129 is: 193.43

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.58 : 632.15 = 129 : x
  2. Step 2: Convert to fraction form
    421.58/632.15 = 129/x
  3. Step 3: Cross multiply
    421.58x = 632.15 × 129
  4. Step 4: Simplify right side
    421.58x = 81,547.35
  5. Step 5: Solve for x
    x = 81,547.35/421.58
  6. Step 6: Final answer
    x = 193.43

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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.