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Finding the Fourth Proportional to 421.80, 632.70 and 312.45

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Solution

The fourth proportional to 421.80, 632.70 and 312.45 is: 468.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    421.80 : 632.70 = 312.45 : x
  2. Step 2: Convert to fraction form
    421.80/632.70 = 312.45/x
  3. Step 3: Cross multiply
    421.80x = 632.70 × 312.45
  4. Step 4: Simplify right side
    421.80x = 197,687.12
  5. Step 5: Solve for x
    x = 197,687.12/421.80
  6. Step 6: Final answer
    x = 468.68

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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.