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Finding the Fourth Proportional to 420.19, 579.35 and 321.79

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Solution

The fourth proportional to 420.19, 579.35 and 321.79 is: 443.67

Step by Step Solution

  1. Step 1: Write the proportion equation
    420.19 : 579.35 = 321.79 : x
  2. Step 2: Convert to fraction form
    420.19/579.35 = 321.79/x
  3. Step 3: Cross multiply
    420.19x = 579.35 × 321.79
  4. Step 4: Simplify right side
    420.19x = 186,427.43
  5. Step 5: Solve for x
    x = 186,427.43/420.19
  6. Step 6: Final answer
    x = 443.67

Related Problems

Find fourth proportional to 210.10, 289.67 and 160.90
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Double scale
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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.