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Finding the Fourth Proportional to 421.60, 631.86 and 205

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Solution

The fourth proportional to 421.60, 631.86 and 205 is: 307.24

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.60 : 631.86 = 205 : x
  2. Step 2: Convert to fraction form
    421.60/631.86 = 205/x
  3. Step 3: Cross multiply
    421.60x = 631.86 × 205
  4. Step 4: Simplify right side
    421.60x = 129,531.30
  5. Step 5: Solve for x
    x = 129,531.30/421.60
  6. Step 6: Final answer
    x = 307.24

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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.