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Finding the Fourth Proportional to 780.17, 1,075.75 and 485.06

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Solution

The fourth proportional to 780.17, 1,075.75 and 485.06 is: 668.83

Step by Step Solution

  1. Step 1: Write the proportion equation
    780.17 : 1,075.75 = 485.06 : x
  2. Step 2: Convert to fraction form
    780.17/1,075.75 = 485.06/x
  3. Step 3: Cross multiply
    780.17x = 1,075.75 × 485.06
  4. Step 4: Simplify right side
    780.17x = 521,796.70
  5. Step 5: Solve for x
    x = 521,796.70/780.17
  6. Step 6: Final answer
    x = 668.83

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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.