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Finding the Fourth Proportional to 975.36, 1,345.08 and 643.21

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Solution

The fourth proportional to 975.36, 1,345.08 and 643.21 is: 887.02

Step by Step Solution

  1. Step 1: Write the proportion equation
    975.36 : 1,345.08 = 643.21 : x
  2. Step 2: Convert to fraction form
    975.36/1,345.08 = 643.21/x
  3. Step 3: Cross multiply
    975.36x = 1,345.08 × 643.21
  4. Step 4: Simplify right side
    975.36x = 865,165.54
  5. Step 5: Solve for x
    x = 865,165.54/975.36
  6. Step 6: Final answer
    x = 887.02

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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.