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Finding the Fourth Proportional to 78, 116.91 and 64.56

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Solution

The fourth proportional to 78, 116.91 and 64.56 is: 96.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    78 : 116.91 = 64.56 : x
  2. Step 2: Convert to fraction form
    78/116.91 = 64.56/x
  3. Step 3: Cross multiply
    78x = 116.91 × 64.56
  4. Step 4: Simplify right side
    78x = 7,547.71
  5. Step 5: Solve for x
    x = 7,547.71/78
  6. Step 6: Final answer
    x = 96.77

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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.