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Finding the Fourth Proportional to 145.68, 218.64 and 90.78

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Solution

The fourth proportional to 145.68, 218.64 and 90.78 is: 136.24

Step by Step Solution

  1. Step 1: Write the proportion equation
    145.68 : 218.64 = 90.78 : x
  2. Step 2: Convert to fraction form
    145.68/218.64 = 90.78/x
  3. Step 3: Cross multiply
    145.68x = 218.64 × 90.78
  4. Step 4: Simplify right side
    145.68x = 19,848.14
  5. Step 5: Solve for x
    x = 19,848.14/145.68
  6. Step 6: Final answer
    x = 136.24

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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.