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Finding the Fourth Proportional to 145, 199.47 and 128.59

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Solution

The fourth proportional to 145, 199.47 and 128.59 is: 176.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    145 : 199.47 = 128.59 : x
  2. Step 2: Convert to fraction form
    145/199.47 = 128.59/x
  3. Step 3: Cross multiply
    145x = 199.47 × 128.59
  4. Step 4: Simplify right side
    145x = 25,649.85
  5. Step 5: Solve for x
    x = 25,649.85/145
  6. Step 6: Final answer
    x = 176.90

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.