Home / 429-640

Finding the Third Proportional to 429 and 640

Calculator

Solution

The third proportional to 429 and 640 is: 954.78

Step by Step Solution

  1. Step 1: Write the proportion equation
    429 : 640 = 640 : x
  2. Step 2: Convert to fraction form
    429/640 = 640/x
  3. Step 3: Cross multiply
    429x = 640 × 640
  4. Step 4: Simplify right side
    429x = 409,600
  5. Step 5: Solve for x
    x = 409,600/429
  6. Step 6: Final answer
    x = 954.78

Related Problems

Find third proportional to 214.50 and 320
Half scale
Find third proportional to 858 and 1,280
Double scale
Find third proportional to 431 and 643
Similar ratio
Find third proportional to 643.50 and 960
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.