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Finding the Fourth Proportional to 970.98, 1,340.16 and 639.43

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Solution

The fourth proportional to 970.98, 1,340.16 and 639.43 is: 882.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    970.98 : 1,340.16 = 639.43 : x
  2. Step 2: Convert to fraction form
    970.98/1,340.16 = 639.43/x
  3. Step 3: Cross multiply
    970.98x = 1,340.16 × 639.43
  4. Step 4: Simplify right side
    970.98x = 856,938.51
  5. Step 5: Solve for x
    x = 856,938.51/970.98
  6. Step 6: Final answer
    x = 882.55

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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.