HELP ME PLZ

It’s just 21 and 22

21) 12 cm

22) 5.9 cm

Step-by-step explanation:

21) The base is 10, and if the other two sides are congruent and the perimeter is 36, we can figure out with simple algebra that the sides are 13 cm long.

Half of 10 is 5, so we can use the pythagorean theorem.

5^2+x^2=13^2

Rearranging the variables we have 169-25=x^2

144=x^2

x can be plus or minus 12, but since negative length is impossible we find that x is positive 12 cm.

22) We want to use sine, because we have opposite and hypotenuse. A simple and easy way to memorize this is the SohCahToa method. If we have opposite (O) and hypotenuse (H) we have OH. Soh has the letters O and H, and the S means we should use sine.

sine 36=a/10

Plug this into a calculator or desmos scientific calculator to get a=5.9

c.

step-by-step explanation:

she should of added 9^2 and 12^2. that is because it is a^2+b^2=c^2. c^2 is the hypotenuse and should always be bigger than the other two numbers. which is why she should of added 9 squared and 12 squared together instead of 15 squared.

i can answer this if i have the answer choices