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Finding the Fourth Proportional to 870.21, 1,305.36 and 436.86

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Solution

The fourth proportional to 870.21, 1,305.36 and 436.86 is: 655.31

Step by Step Solution

  1. Step 1: Write the proportion equation
    870.21 : 1,305.36 = 436.86 : x
  2. Step 2: Convert to fraction form
    870.21/1,305.36 = 436.86/x
  3. Step 3: Cross multiply
    870.21x = 1,305.36 × 436.86
  4. Step 4: Simplify right side
    870.21x = 570,259.57
  5. Step 5: Solve for x
    x = 570,259.57/870.21
  6. Step 6: Final answer
    x = 655.31

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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.