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Finding the Fourth Proportional to 918.42, 1,375.34 and 643.22

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Solution

The fourth proportional to 918.42, 1,375.34 and 643.22 is: 963.23

Step by Step Solution

  1. Step 1: Write the proportion equation
    918.42 : 1,375.34 = 643.22 : x
  2. Step 2: Convert to fraction form
    918.42/1,375.34 = 643.22/x
  3. Step 3: Cross multiply
    918.42x = 1,375.34 × 643.22
  4. Step 4: Simplify right side
    918.42x = 884,646.19
  5. Step 5: Solve for x
    x = 884,646.19/918.42
  6. Step 6: Final answer
    x = 963.23

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.