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Finding the Fourth Proportional to 958.02, 1,320.78 and 643.35

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Solution

The fourth proportional to 958.02, 1,320.78 and 643.35 is: 886.96

Step by Step Solution

  1. Step 1: Write the proportion equation
    958.02 : 1,320.78 = 643.35 : x
  2. Step 2: Convert to fraction form
    958.02/1,320.78 = 643.35/x
  3. Step 3: Cross multiply
    958.02x = 1,320.78 × 643.35
  4. Step 4: Simplify right side
    958.02x = 849,723.81
  5. Step 5: Solve for x
    x = 849,723.81/958.02
  6. Step 6: Final answer
    x = 886.96

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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.