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Finding the Fourth Proportional to 992.76, 1,369.50 and 643.56

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Solution

The fourth proportional to 992.76, 1,369.50 and 643.56 is: 887.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    992.76 : 1,369.50 = 643.56 : x
  2. Step 2: Convert to fraction form
    992.76/1,369.50 = 643.56/x
  3. Step 3: Cross multiply
    992.76x = 1,369.50 × 643.56
  4. Step 4: Simplify right side
    992.76x = 881,355.42
  5. Step 5: Solve for x
    x = 881,355.42/992.76
  6. Step 6: Final answer
    x = 887.78

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.