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Finding the Fourth Proportional to 918.76, 1,268.46 and 638.90

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Solution

The fourth proportional to 918.76, 1,268.46 and 638.90 is: 882.08

Step by Step Solution

  1. Step 1: Write the proportion equation
    918.76 : 1,268.46 = 638.90 : x
  2. Step 2: Convert to fraction form
    918.76/1,268.46 = 638.90/x
  3. Step 3: Cross multiply
    918.76x = 1,268.46 × 638.90
  4. Step 4: Simplify right side
    918.76x = 810,419.09
  5. Step 5: Solve for x
    x = 810,419.09/918.76
  6. Step 6: Final answer
    x = 882.08

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1.5x scale

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.