Answer :

chetankachana

Answer:

c = 110.25

(r + 10.5)²

Step-by-step explanation:

Hello!

Perfect Square Trinomial: [tex](a + b)^2 = a^2 + 2ab + b^2[/tex]

21r is basically 2 times r and b, the missing number.

Solve for b

  • 21r = 2*r*b
  • 10.5 = b

The missing number, b, would be 10.5

Now c is basically b², so we just have to simplify 10.5²:

  • 10.5²
  • 110.25

c should be 110.25 for it to be a Perfect Square Trinomial. The factored form would be (r + 10.5)².

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