Answer:
28
Step-by-step explanation:
Use the pythagorean theorem and solve for a:
a² + b² = c²
a² + 21² = 35²
a² + 441 = 1225
a² = 784
a = 28
So, the missing length is 28.
Answer
Pretty sure it's SQ.
x(4x^2 + 20x + 24)
4x(x^2 + 5x + 6)
4x(x+3)(x+2)