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Finding the Fourth Proportional to 71.68, 98.88 and 64.72

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Solution

The fourth proportional to 71.68, 98.88 and 64.72 is: 89.28

Step by Step Solution

  1. Step 1: Write the proportion equation
    71.68 : 98.88 = 64.72 : x
  2. Step 2: Convert to fraction form
    71.68/98.88 = 64.72/x
  3. Step 3: Cross multiply
    71.68x = 98.88 × 64.72
  4. Step 4: Simplify right side
    71.68x = 6,399.51
  5. Step 5: Solve for x
    x = 6,399.51/71.68
  6. Step 6: Final answer
    x = 89.28

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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.