Home / 813.20-1,218.80-553.20

Finding the Fourth Proportional to 813.20, 1,218.80 and 553.20

Calculator

Solution

The fourth proportional to 813.20, 1,218.80 and 553.20 is: 829.12

Step by Step Solution

  1. Step 1: Write the proportion equation
    813.20 : 1,218.80 = 553.20 : x
  2. Step 2: Convert to fraction form
    813.20/1,218.80 = 553.20/x
  3. Step 3: Cross multiply
    813.20x = 1,218.80 × 553.20
  4. Step 4: Simplify right side
    813.20x = 674,240.16
  5. Step 5: Solve for x
    x = 674,240.16/813.20
  6. Step 6: Final answer
    x = 829.12

Related Problems

Find fourth proportional to 406.60, 609.40 and 276.60
Half scale
Find fourth proportional to 1,626.40, 2,437.60 and 1,106.40
Double scale
Find fourth proportional to 814.20, 1,220.30 and 554.20
Similar ratio
Find fourth proportional to 1,219.80, 1,828.20 and 829.80
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.