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Finding the Fourth Proportional to 438.28, 657.34 and 145.78

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Solution

The fourth proportional to 438.28, 657.34 and 145.78 is: 218.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    438.28 : 657.34 = 145.78 : x
  2. Step 2: Convert to fraction form
    438.28/657.34 = 145.78/x
  3. Step 3: Cross multiply
    438.28x = 657.34 × 145.78
  4. Step 4: Simplify right side
    438.28x = 95,828.71
  5. Step 5: Solve for x
    x = 95,828.71/438.28
  6. Step 6: Final answer
    x = 218.65

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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.