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Finding the Fourth Proportional to 840.87, 1,160.87 and 643.77

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Solution

The fourth proportional to 840.87, 1,160.87 and 643.77 is: 888.76

Step by Step Solution

  1. Step 1: Write the proportion equation
    840.87 : 1,160.87 = 643.77 : x
  2. Step 2: Convert to fraction form
    840.87/1,160.87 = 643.77/x
  3. Step 3: Cross multiply
    840.87x = 1,160.87 × 643.77
  4. Step 4: Simplify right side
    840.87x = 747,330.06
  5. Step 5: Solve for x
    x = 747,330.06/840.87
  6. Step 6: Final answer
    x = 888.76

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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.