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Finding the Fourth Proportional to 145.90, 218.40 and 129.70

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Solution

The fourth proportional to 145.90, 218.40 and 129.70 is: 194.15

Step by Step Solution

  1. Step 1: Write the proportion equation
    145.90 : 218.40 = 129.70 : x
  2. Step 2: Convert to fraction form
    145.90/218.40 = 129.70/x
  3. Step 3: Cross multiply
    145.90x = 218.40 × 129.70
  4. Step 4: Simplify right side
    145.90x = 28,326.48
  5. Step 5: Solve for x
    x = 28,326.48/145.90
  6. Step 6: Final answer
    x = 194.15

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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.