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Finding the Fourth Proportional to 772.90, 1,159.35 and 643.30

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Solution

The fourth proportional to 772.90, 1,159.35 and 643.30 is: 964.95

Step by Step Solution

  1. Step 1: Write the proportion equation
    772.90 : 1,159.35 = 643.30 : x
  2. Step 2: Convert to fraction form
    772.90/1,159.35 = 643.30/x
  3. Step 3: Cross multiply
    772.90x = 1,159.35 × 643.30
  4. Step 4: Simplify right side
    772.90x = 745,809.86
  5. Step 5: Solve for x
    x = 745,809.86/772.90
  6. Step 6: Final answer
    x = 964.95

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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.