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Finding the Fourth Proportional to 870.11, 1,305.16 and 431.27

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Solution

The fourth proportional to 870.11, 1,305.16 and 431.27 is: 646.90

Step by Step Solution

  1. Step 1: Write the proportion equation
    870.11 : 1,305.16 = 431.27 : x
  2. Step 2: Convert to fraction form
    870.11/1,305.16 = 431.27/x
  3. Step 3: Cross multiply
    870.11x = 1,305.16 × 431.27
  4. Step 4: Simplify right side
    870.11x = 562,868.75
  5. Step 5: Solve for x
    x = 562,868.75/870.11
  6. Step 6: Final answer
    x = 646.90

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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.