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Finding the Fourth Proportional to 870.97, 1,307.10 and 640.47

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Solution

The fourth proportional to 870.97, 1,307.10 and 640.47 is: 961.18

Step by Step Solution

  1. Step 1: Write the proportion equation
    870.97 : 1,307.10 = 640.47 : x
  2. Step 2: Convert to fraction form
    870.97/1,307.10 = 640.47/x
  3. Step 3: Cross multiply
    870.97x = 1,307.10 × 640.47
  4. Step 4: Simplify right side
    870.97x = 837,158.34
  5. Step 5: Solve for x
    x = 837,158.34/870.97
  6. Step 6: Final answer
    x = 961.18

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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.