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Finding the Fourth Proportional to 428.96, 643.80 and 185.67

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Solution

The fourth proportional to 428.96, 643.80 and 185.67 is: 278.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.96 : 643.80 = 185.67 : x
  2. Step 2: Convert to fraction form
    428.96/643.80 = 185.67/x
  3. Step 3: Cross multiply
    428.96x = 643.80 × 185.67
  4. Step 4: Simplify right side
    428.96x = 119,534.35
  5. Step 5: Solve for x
    x = 119,534.35/428.96
  6. Step 6: Final answer
    x = 278.66

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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.