Home / 432.20-643.50-429.80

Finding the Fourth Proportional to 432.20, 643.50 and 429.80

Calculator

Solution

The fourth proportional to 432.20, 643.50 and 429.80 is: 639.93

Step by Step Solution

  1. Step 1: Write the proportion equation
    432.20 : 643.50 = 429.80 : x
  2. Step 2: Convert to fraction form
    432.20/643.50 = 429.80/x
  3. Step 3: Cross multiply
    432.20x = 643.50 × 429.80
  4. Step 4: Simplify right side
    432.20x = 276,576.30
  5. Step 5: Solve for x
    x = 276,576.30/432.20
  6. Step 6: Final answer
    x = 639.93

Related Problems

Find fourth proportional to 216.10, 321.75 and 214.90
Half scale
Find fourth proportional to 864.40, 1,287 and 859.60
Double scale
Find fourth proportional to 433.20, 644.99 and 430.80
Similar ratio
Find fourth proportional to 648.30, 965.25 and 644.70
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.