A² = c² - b²
a² = 21² - 13 ²
a² = 441 - 169
a² = 272
a = √272 = 16.49242 ≈ 16.49
Answer : D ) 16.49
G(x)=1
-3x2+18x+2
-6+18+2
6+2
8
Because if you multiply 2 different irrational numbers (like the following)

You will get an irrational answer.
BUT
if you multiply the same square root (which are both irrational, you get a rational number)
HI
the answer is 200 millimeters
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Answer:c
Step-by-step explanation: