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Finding the Fourth Proportional to 145.02, 217.77 and 138.78

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Solution

The fourth proportional to 145.02, 217.77 and 138.78 is: 208.40

Step by Step Solution

  1. Step 1: Write the proportion equation
    145.02 : 217.77 = 138.78 : x
  2. Step 2: Convert to fraction form
    145.02/217.77 = 138.78/x
  3. Step 3: Cross multiply
    145.02x = 217.77 × 138.78
  4. Step 4: Simplify right side
    145.02x = 30,222.12
  5. Step 5: Solve for x
    x = 30,222.12/145.02
  6. Step 6: Final answer
    x = 208.40

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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.