Home / 291.09-639.77

Finding the Third Proportional to 291.09 and 639.77

Calculator

Solution

The third proportional to 291.09 and 639.77 is: 1,406.11

Step by Step Solution

  1. Step 1: Write the proportion equation
    291.09 : 639.77 = 639.77 : x
  2. Step 2: Convert to fraction form
    291.09/639.77 = 639.77/x
  3. Step 3: Cross multiply
    291.09x = 639.77 × 639.77
  4. Step 4: Simplify right side
    291.09x = 409,310.05
  5. Step 5: Solve for x
    x = 409,310.05/291.09
  6. Step 6: Final answer
    x = 1,406.11

Related Problems

Find third proportional to 145.55 and 319.89
Half scale
Find third proportional to 582.19 and 1,279.55
Double scale
Find third proportional to 293 and 644
Similar ratio
Find third proportional to 436.64 and 959.66
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (2.20) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.