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Finding the Fourth Proportional to 920.77, 1,270.79 and 640.51

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Solution

The fourth proportional to 920.77, 1,270.79 and 640.51 is: 883.99

Step by Step Solution

  1. Step 1: Write the proportion equation
    920.77 : 1,270.79 = 640.51 : x
  2. Step 2: Convert to fraction form
    920.77/1,270.79 = 640.51/x
  3. Step 3: Cross multiply
    920.77x = 1,270.79 × 640.51
  4. Step 4: Simplify right side
    920.77x = 813,949.73
  5. Step 5: Solve for x
    x = 813,949.73/920.77
  6. Step 6: Final answer
    x = 883.99

Related Problems

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Half scale
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Double scale
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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.