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Finding the Fourth Proportional to 780.58, 1,170.46 and 691.76

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Solution

The fourth proportional to 780.58, 1,170.46 and 691.76 is: 1,037.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    780.58 : 1,170.46 = 691.76 : x
  2. Step 2: Convert to fraction form
    780.58/1,170.46 = 691.76/x
  3. Step 3: Cross multiply
    780.58x = 1,170.46 × 691.76
  4. Step 4: Simplify right side
    780.58x = 809,681.20
  5. Step 5: Solve for x
    x = 809,681.20/780.58
  6. Step 6: Final answer
    x = 1,037.28

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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.