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Finding the Fourth Proportional to 881.12, 1,216.40 and 840.16

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Solution

The fourth proportional to 881.12, 1,216.40 and 840.16 is: 1,159.85

Step by Step Solution

  1. Step 1: Write the proportion equation
    881.12 : 1,216.40 = 840.16 : x
  2. Step 2: Convert to fraction form
    881.12/1,216.40 = 840.16/x
  3. Step 3: Cross multiply
    881.12x = 1,216.40 × 840.16
  4. Step 4: Simplify right side
    881.12x = 1,021,970.62
  5. Step 5: Solve for x
    x = 1,021,970.62/881.12
  6. Step 6: Final answer
    x = 1,159.85

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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.