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Finding the Fourth Proportional to 145.47, 219 and 128.70

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Solution

The fourth proportional to 145.47, 219 and 128.70 is: 193.75

Step by Step Solution

  1. Step 1: Write the proportion equation
    145.47 : 219 = 128.70 : x
  2. Step 2: Convert to fraction form
    145.47/219 = 128.70/x
  3. Step 3: Cross multiply
    145.47x = 219 × 128.70
  4. Step 4: Simplify right side
    145.47x = 28,185.30
  5. Step 5: Solve for x
    x = 28,185.30/145.47
  6. Step 6: Final answer
    x = 193.75

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Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.