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Finding the Fourth Proportional to 780.64, 1,075.68 and 691.34

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Solution

The fourth proportional to 780.64, 1,075.68 and 691.34 is: 952.63

Step by Step Solution

  1. Step 1: Write the proportion equation
    780.64 : 1,075.68 = 691.34 : x
  2. Step 2: Convert to fraction form
    780.64/1,075.68 = 691.34/x
  3. Step 3: Cross multiply
    780.64x = 1,075.68 × 691.34
  4. Step 4: Simplify right side
    780.64x = 743,655.23
  5. Step 5: Solve for x
    x = 743,655.23/780.64
  6. Step 6: Final answer
    x = 952.63

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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.