Home / 428.85-643.50-234

Finding the Fourth Proportional to 428.85, 643.50 and 234

Calculator

Solution

The fourth proportional to 428.85, 643.50 and 234 is: 351.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    428.85 : 643.50 = 234 : x
  2. Step 2: Convert to fraction form
    428.85/643.50 = 234/x
  3. Step 3: Cross multiply
    428.85x = 643.50 × 234
  4. Step 4: Simplify right side
    428.85x = 150,579
  5. Step 5: Solve for x
    x = 150,579/428.85
  6. Step 6: Final answer
    x = 351.12

Related Problems

Find fourth proportional to 214.43, 321.75 and 117
Half scale
Find fourth proportional to 857.70, 1,287 and 468
Double scale
Find fourth proportional to 429.85, 645 and 235
Similar ratio
Find fourth proportional to 643.28, 965.25 and 351
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.