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Finding the Fourth Proportional to 145.80, 218.64 and 139.80

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Solution

The fourth proportional to 145.80, 218.64 and 139.80 is: 209.64

Step by Step Solution

  1. Step 1: Write the proportion equation
    145.80 : 218.64 = 139.80 : x
  2. Step 2: Convert to fraction form
    145.80/218.64 = 139.80/x
  3. Step 3: Cross multiply
    145.80x = 218.64 × 139.80
  4. Step 4: Simplify right side
    145.80x = 30,565.87
  5. Step 5: Solve for x
    x = 30,565.87/145.80
  6. Step 6: Final answer
    x = 209.64

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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.