Home / 489.05-734.28-428.91

Finding the Fourth Proportional to 489.05, 734.28 and 428.91

Calculator

Solution

The fourth proportional to 489.05, 734.28 and 428.91 is: 643.98

Step by Step Solution

  1. Step 1: Write the proportion equation
    489.05 : 734.28 = 428.91 : x
  2. Step 2: Convert to fraction form
    489.05/734.28 = 428.91/x
  3. Step 3: Cross multiply
    489.05x = 734.28 × 428.91
  4. Step 4: Simplify right side
    489.05x = 314,942.22
  5. Step 5: Solve for x
    x = 314,942.22/489.05
  6. Step 6: Final answer
    x = 643.98

Related Problems

Find fourth proportional to 244.53, 367.14 and 214.46
Half scale
Find fourth proportional to 978.11, 1,468.56 and 857.82
Double scale
Find fourth proportional to 490.05, 735.78 and 429.91
Similar ratio
Find fourth proportional to 733.58, 1,101.42 and 643.37
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.