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Finding the Fourth Proportional to 970.88, 1,339.32 and 621.20

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Solution

The fourth proportional to 970.88, 1,339.32 and 621.20 is: 856.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    970.88 : 1,339.32 = 621.20 : x
  2. Step 2: Convert to fraction form
    970.88/1,339.32 = 621.20/x
  3. Step 3: Cross multiply
    970.88x = 1,339.32 × 621.20
  4. Step 4: Simplify right side
    970.88x = 831,985.58
  5. Step 5: Solve for x
    x = 831,985.58/970.88
  6. Step 6: Final answer
    x = 856.94

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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.