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Finding the Fourth Proportional to 870.57, 1,305.80 and 408.45

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Solution

The fourth proportional to 870.57, 1,305.80 and 408.45 is: 612.65

Step by Step Solution

  1. Step 1: Write the proportion equation
    870.57 : 1,305.80 = 408.45 : x
  2. Step 2: Convert to fraction form
    870.57/1,305.80 = 408.45/x
  3. Step 3: Cross multiply
    870.57x = 1,305.80 × 408.45
  4. Step 4: Simplify right side
    870.57x = 533,356.25
  5. Step 5: Solve for x
    x = 533,356.25/870.57
  6. Step 6: Final answer
    x = 612.65

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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.