Round to the nearest tenth

9514 1404 393

  21.4  

Step-by-step explanation:

For this problem, you only need to know that the hypotenuse (x) is the longest side of the triangle. The only answer choice longer than 20 is ...

  x = 21.4

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If you want to actually go through the numbers, you know that ...

  Cos = Adjacent/Hypotenuse

  cos(21°) = 20/x

  x = 20/cos(21°)

  x ≈ 21.4

hello from mrbilldoesmath!

answer:

(7 x + 6 y) (49 x^2 - 42 x y + 36 y^2)

discussion:

the trick is to recognize that 343 = 7^3 and 216 = 6^3 and, in general,

a^3 + b^3 =   (a + b) (a^2 - a b + b^2).

in our case

343x^3+216y^3   =   (7x)^3 + (6y)^3

so take a = 7x and b = 6y in the above equation to get the answer.

you,

mrb