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Finding the Fourth Proportional to 280.16, 386.61 and 155.81

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Solution

The fourth proportional to 280.16, 386.61 and 155.81 is: 215.01

Step by Step Solution

  1. Step 1: Write the proportion equation
    280.16 : 386.61 = 155.81 : x
  2. Step 2: Convert to fraction form
    280.16/386.61 = 155.81/x
  3. Step 3: Cross multiply
    280.16x = 386.61 × 155.81
  4. Step 4: Simplify right side
    280.16x = 60,235.77
  5. Step 5: Solve for x
    x = 60,235.77/280.16
  6. Step 6: Final answer
    x = 215.01

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.