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Finding the Fourth Proportional to 305.02, 420.78 and 211.60

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Solution

The fourth proportional to 305.02, 420.78 and 211.60 is: 291.91

Step by Step Solution

  1. Step 1: Write the proportion equation
    305.02 : 420.78 = 211.60 : x
  2. Step 2: Convert to fraction form
    305.02/420.78 = 211.60/x
  3. Step 3: Cross multiply
    305.02x = 420.78 × 211.60
  4. Step 4: Simplify right side
    305.02x = 89,037.05
  5. Step 5: Solve for x
    x = 89,037.05/305.02
  6. Step 6: Final answer
    x = 291.91

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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.