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Finding the Fourth Proportional to 260.51, 390.69 and 87.15

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Solution

The fourth proportional to 260.51, 390.69 and 87.15 is: 130.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    260.51 : 390.69 = 87.15 : x
  2. Step 2: Convert to fraction form
    260.51/390.69 = 87.15/x
  3. Step 3: Cross multiply
    260.51x = 390.69 × 87.15
  4. Step 4: Simplify right side
    260.51x = 34,048.63
  5. Step 5: Solve for x
    x = 34,048.63/260.51
  6. Step 6: Final answer
    x = 130.70

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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.