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Finding the Fourth Proportional to 869.70, 1,305.90 and 772.50

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Solution

The fourth proportional to 869.70, 1,305.90 and 772.50 is: 1,159.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    869.70 : 1,305.90 = 772.50 : x
  2. Step 2: Convert to fraction form
    869.70/1,305.90 = 772.50/x
  3. Step 3: Cross multiply
    869.70x = 1,305.90 × 772.50
  4. Step 4: Simplify right side
    869.70x = 1,008,807.75
  5. Step 5: Solve for x
    x = 1,008,807.75/869.70
  6. Step 6: Final answer
    x = 1,159.95

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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.