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Finding the Fourth Proportional to 870.12, 1,304.64 and 485.28

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Solution

The fourth proportional to 870.12, 1,304.64 and 485.28 is: 727.62

Step by Step Solution

  1. Step 1: Write the proportion equation
    870.12 : 1,304.64 = 485.28 : x
  2. Step 2: Convert to fraction form
    870.12/1,304.64 = 485.28/x
  3. Step 3: Cross multiply
    870.12x = 1,304.64 × 485.28
  4. Step 4: Simplify right side
    870.12x = 633,115.70
  5. Step 5: Solve for x
    x = 633,115.70/870.12
  6. Step 6: Final answer
    x = 727.62

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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.