Question

noah tried to prove that $cos(\theta) = sin(\theta)$ using the following diagram. his proof is not correct.

statement	reason
2 $sin(\theta) = \frac{ab}{bc}$	definition of sine.
3 $cos(mangle b) = \frac{ab}{bc}$	definition of cosine.
4 $cos(\theta) = \frac{ab}{bc}$	substitution.
5 $cos(\theta) = sin(\theta)$	substitution

what is the first mistake in noahs proof?
choose 1 answer:
a) angles $angle b$ and $angle c$ are complementary, not congruent.
b) noah used the wrong sides in his ratio for $sin(\theta)$.
c) noah used the wrong sides in his ratio for

Explanation:

El primer error está en el primer paso: en un triángulo rectángulo, los ángulos agudos son complementarios (suman 90°), no congruentes (iguales). Esto invalida la afirmación inicial que $m\angle B = \theta$.

Answer:

A. Angles $\angle B$ and $\angle C$ are complementary, not congruent.