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Finding the Fourth Proportional to 781, 1,077.67 and 663.45

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Solution

The fourth proportional to 781, 1,077.67 and 663.45 is: 915.47

Step by Step Solution

  1. Step 1: Write the proportion equation
    781 : 1,077.67 = 663.45 : x
  2. Step 2: Convert to fraction form
    781/1,077.67 = 663.45/x
  3. Step 3: Cross multiply
    781x = 1,077.67 × 663.45
  4. Step 4: Simplify right side
    781x = 714,980.16
  5. Step 5: Solve for x
    x = 714,980.16/781
  6. Step 6: Final answer
    x = 915.47

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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.