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Finding the Fourth Proportional to 912.72, 1,359.50 and 870.64

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Solution

The fourth proportional to 912.72, 1,359.50 and 870.64 is: 1,296.82

Step by Step Solution

  1. Step 1: Write the proportion equation
    912.72 : 1,359.50 = 870.64 : x
  2. Step 2: Convert to fraction form
    912.72/1,359.50 = 870.64/x
  3. Step 3: Cross multiply
    912.72x = 1,359.50 × 870.64
  4. Step 4: Simplify right side
    912.72x = 1,183,635.08
  5. Step 5: Solve for x
    x = 1,183,635.08/912.72
  6. Step 6: Final answer
    x = 1,296.82

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Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.