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Finding the Fourth Proportional to 145.63, 218.51 and 77.21

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Solution

The fourth proportional to 145.63, 218.51 and 77.21 is: 115.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    145.63 : 218.51 = 77.21 : x
  2. Step 2: Convert to fraction form
    145.63/218.51 = 77.21/x
  3. Step 3: Cross multiply
    145.63x = 218.51 × 77.21
  4. Step 4: Simplify right side
    145.63x = 16,871.16
  5. Step 5: Solve for x
    x = 16,871.16/145.63
  6. Step 6: Final answer
    x = 115.85

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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.