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Finding the Fourth Proportional to 870.21, 1,305.11 and 431.01

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Solution

The fourth proportional to 870.21, 1,305.11 and 431.01 is: 646.41

Step by Step Solution

  1. Step 1: Write the proportion equation
    870.21 : 1,305.11 = 431.01 : x
  2. Step 2: Convert to fraction form
    870.21/1,305.11 = 431.01/x
  3. Step 3: Cross multiply
    870.21x = 1,305.11 × 431.01
  4. Step 4: Simplify right side
    870.21x = 562,513.31
  5. Step 5: Solve for x
    x = 562,513.31/870.21
  6. Step 6: Final answer
    x = 646.41

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Double scale
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1.5x scale

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.