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Finding the Fourth Proportional to 972.20, 1,342.47 and 640.51

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Solution

The fourth proportional to 972.20, 1,342.47 and 640.51 is: 884.45

Step by Step Solution

  1. Step 1: Write the proportion equation
    972.20 : 1,342.47 = 640.51 : x
  2. Step 2: Convert to fraction form
    972.20/1,342.47 = 640.51/x
  3. Step 3: Cross multiply
    972.20x = 1,342.47 × 640.51
  4. Step 4: Simplify right side
    972.20x = 859,864.51
  5. Step 5: Solve for x
    x = 859,864.51/972.20
  6. Step 6: Final answer
    x = 884.45

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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.