Home / 428.48-639.92

Finding the Third Proportional to 428.48 and 639.92

Calculator

Solution

The third proportional to 428.48 and 639.92 is: 955.70

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.48 : 639.92 = 639.92 : x
  2. Step 2: Convert to fraction form
    428.48/639.92 = 639.92/x
  3. Step 3: Cross multiply
    428.48x = 639.92 × 639.92
  4. Step 4: Simplify right side
    428.48x = 409,499.85
  5. Step 5: Solve for x
    x = 409,499.85/428.48
  6. Step 6: Final answer
    x = 955.70

Related Problems

Find third proportional to 214.24 and 319.96
Half scale
Find third proportional to 856.97 and 1,279.84
Double scale
Find third proportional to 430 and 643
Similar ratio
Find third proportional to 642.72 and 959.88
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.49) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.