Simplify square root of 3 times square root of 21

Step-by-step explanation: To multiply the square root of 3 times the square root of 21, we simply multiply the numbers that are inside the square roots together.

So, root 21 × root 3 equals root 63.

Next, we simplify the square root of 63. 63 factors as 3 x 21 and 21 factors as 3 x 7. So we have a pair of 3's which means a 3 can come out of the radical and the 7 doesn't pair up stays in the radical so our final answer is .

second option

step-by-step explanation:

the measures of a triangle equal 180. use that to find x.

2x+3x+4x=180

9x=180

9x/9=180/9

x=20

now you know x, you know angle a is 40°, angle b is 60°, angle c is 80°.

because angle a is 40°, the first option doesn't work.

because angle b is 60°, the second option does work.

when you add angle a and b, you get 100°. complementary means it equals 90°, so the third option doesn't work.

when you add angle a and c, you get 120°, which is not 100.