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Finding the Fourth Proportional to 810.66, 1,214.34 and 420.24

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Solution

The fourth proportional to 810.66, 1,214.34 and 420.24 is: 629.50

Step by Step Solution

  1. Step 1: Write the proportion equation
    810.66 : 1,214.34 = 420.24 : x
  2. Step 2: Convert to fraction form
    810.66/1,214.34 = 420.24/x
  3. Step 3: Cross multiply
    810.66x = 1,214.34 × 420.24
  4. Step 4: Simplify right side
    810.66x = 510,314.24
  5. Step 5: Solve for x
    x = 510,314.24/810.66
  6. Step 6: Final answer
    x = 629.50

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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.