Home / 429.19-643.98-209.75

Finding the Fourth Proportional to 429.19, 643.98 and 209.75

Calculator

Solution

The fourth proportional to 429.19, 643.98 and 209.75 is: 314.72

Step by Step Solution

  1. Step 1: Write the proportion equation
    429.19 : 643.98 = 209.75 : x
  2. Step 2: Convert to fraction form
    429.19/643.98 = 209.75/x
  3. Step 3: Cross multiply
    429.19x = 643.98 × 209.75
  4. Step 4: Simplify right side
    429.19x = 135,075.37
  5. Step 5: Solve for x
    x = 135,075.37/429.19
  6. Step 6: Final answer
    x = 314.72

Related Problems

Find fourth proportional to 214.60, 321.99 and 104.88
Half scale
Find fourth proportional to 858.39, 1,287.95 and 419.51
Double scale
Find fourth proportional to 430.19, 645.48 and 210.75
Similar ratio
Find fourth proportional to 643.79, 965.96 and 314.63
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.