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Finding the Fourth Proportional to 918.95, 1,267.90 and 638.87

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Solution

The fourth proportional to 918.95, 1,267.90 and 638.87 is: 881.46

Step by Step Solution

  1. Step 1: Write the proportion equation
    918.95 : 1,267.90 = 638.87 : x
  2. Step 2: Convert to fraction form
    918.95/1,267.90 = 638.87/x
  3. Step 3: Cross multiply
    918.95x = 1,267.90 × 638.87
  4. Step 4: Simplify right side
    918.95x = 810,015.34
  5. Step 5: Solve for x
    x = 810,015.34/918.95
  6. Step 6: Final answer
    x = 881.46

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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.