Home / 556.80-838.40-428.80

Finding the Fourth Proportional to 556.80, 838.40 and 428.80

Calculator

Solution

The fourth proportional to 556.80, 838.40 and 428.80 is: 645.66

Step by Step Solution

  1. Step 1: Write the proportion equation
    556.80 : 838.40 = 428.80 : x
  2. Step 2: Convert to fraction form
    556.80/838.40 = 428.80/x
  3. Step 3: Cross multiply
    556.80x = 838.40 × 428.80
  4. Step 4: Simplify right side
    556.80x = 359,505.92
  5. Step 5: Solve for x
    x = 359,505.92/556.80
  6. Step 6: Final answer
    x = 645.66

Related Problems

Find fourth proportional to 278.40, 419.20 and 214.40
Half scale
Find fourth proportional to 1,113.60, 1,676.80 and 857.60
Double scale
Find fourth proportional to 557.80, 839.91 and 429.80
Similar ratio
Find fourth proportional to 835.20, 1,257.60 and 643.20
1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.51) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.