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Finding the Fourth Proportional to 865.38, 1,289.72 and 864.01

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Solution

The fourth proportional to 865.38, 1,289.72 and 864.01 is: 1,287.68

Step by Step Solution

  1. Step 1: Write the proportion equation
    865.38 : 1,289.72 = 864.01 : x
  2. Step 2: Convert to fraction form
    865.38/1,289.72 = 864.01/x
  3. Step 3: Cross multiply
    865.38x = 1,289.72 × 864.01
  4. Step 4: Simplify right side
    865.38x = 1,114,330.98
  5. Step 5: Solve for x
    x = 1,114,330.98/865.38
  6. Step 6: Final answer
    x = 1,287.68

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1.5x scale

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.