Pythagoras Theorem

Question

a^2+b^2=c^2.

(83−Y)^2+25^2=69^2.

(83−Y)^2=69^2−25^2.

(83−Y)^2=√4136≈18,7.

18,7^2+25^2=X^2. X^2=√974,69=31,22≈31.

Can you explane how the answer 18,7 is calculated.

I am unable to get that number on my calculater,

by using the root function.

Answer 1

Line 4 is incorrect:

(83 - y)² = 4136

83 - y = √4136

83 - y = 64.1174

-y = -18.688