Are the triangles similar? Yes, by the AA rule.
Yes, by the SSS rule.
Not similar.
Yes, by the SS rule.

Yes, by the AA rule.

Step-by-step explanation:

You can see that in both triangles, angle BCD (at the top of the triangle) is marked with the same symbol. This tells us that the two angles are equal.

The same applies with angles CDB (bottom right of the triangle).

We know that all the angles in a triangle add up to 180 degrees, so if two out of the three angles are the same in both triangles, then the third must be equal as well if the angles have to add up to 180.

Therefore, the angles in both triangles correspond, so the triangles are similar by the AA or AAA rule.

since your problem is x^4 = 81, what you have to undeo is the "to the fourth power" part.

the inverse (opposite operation) of "to the fourth power" is "to the fourth root".

  (x^4) ^ ¼   = 81 ^ ¼  

  81 = 3^4     so (3 ^ 4) ^ ¼   =   3 ^ 1   = 3

by hand: (3 ^ 4) ^ ¼   =   3 ^ (4 x ¼) = 3 ^ 1   = 3   (when you take a power to a power, multiply the exponents.)

or, do it by calculator. one way of finding the fourth root is to use ^ (1/4)

step-by-step explanation: