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Finding the Fourth Proportional to 920.80, 1,271.28 and 659.68

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Solution

The fourth proportional to 920.80, 1,271.28 and 659.68 is: 910.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    920.80 : 1,271.28 = 659.68 : x
  2. Step 2: Convert to fraction form
    920.80/1,271.28 = 659.68/x
  3. Step 3: Cross multiply
    920.80x = 1,271.28 × 659.68
  4. Step 4: Simplify right side
    920.80x = 838,637.99
  5. Step 5: Solve for x
    x = 838,637.99/920.80
  6. Step 6: Final answer
    x = 910.77

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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.