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Finding the Fourth Proportional to 780.64, 1,170.70 and 260.50

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Solution

The fourth proportional to 780.64, 1,170.70 and 260.50 is: 390.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    780.64 : 1,170.70 = 260.50 : x
  2. Step 2: Convert to fraction form
    780.64/1,170.70 = 260.50/x
  3. Step 3: Cross multiply
    780.64x = 1,170.70 × 260.50
  4. Step 4: Simplify right side
    780.64x = 304,967.43
  5. Step 5: Solve for x
    x = 304,967.43/780.64
  6. Step 6: Final answer
    x = 390.66

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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.