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Finding the Fourth Proportional to 870.64, 1,307.12 and 505.69

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Solution

The fourth proportional to 870.64, 1,307.12 and 505.69 is: 759.20

Step by Step Solution

  1. Step 1: Write the proportion equation
    870.64 : 1,307.12 = 505.69 : x
  2. Step 2: Convert to fraction form
    870.64/1,307.12 = 505.69/x
  3. Step 3: Cross multiply
    870.64x = 1,307.12 × 505.69
  4. Step 4: Simplify right side
    870.64x = 660,991.72
  5. Step 5: Solve for x
    x = 660,991.72/870.64
  6. Step 6: Final answer
    x = 759.20

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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.