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Finding the Fourth Proportional to 864.30, 1,189.32 and 781.50

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Solution

The fourth proportional to 864.30, 1,189.32 and 781.50 is: 1,075.38

Step by Step Solution

  1. Step 1: Write the proportion equation
    864.30 : 1,189.32 = 781.50 : x
  2. Step 2: Convert to fraction form
    864.30/1,189.32 = 781.50/x
  3. Step 3: Cross multiply
    864.30x = 1,189.32 × 781.50
  4. Step 4: Simplify right side
    864.30x = 929,453.58
  5. Step 5: Solve for x
    x = 929,453.58/864.30
  6. Step 6: Final answer
    x = 1,075.38

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.