Question

The right triangle shown has angles X, Y, and Z and side lengths a, b, and

c. Which equation is NOT true for this triangle?

Answer 1

So attached is a picture of the triangle you are talking about and listed under are the choices:

A.) Cos Z=b/c
B.) Sin X=c/b
C.) Tan X=b/a
D.) Tan Z=a/b

The answer would then be B. SinX = c/b.

Just remember SOH CAH TOA:

Sinθ= Opposite Cosθ = Adjacent Tanθ= Opposite
Hypotenuse Hypotenuse Adjacent

Using the triangle in the scenario, you just need to identify which side is which.

Given m∠Z
Adjacent = b
Opposite = a
Hypotenuse = c

SinZ= a CosZ = b TanZ= a
c c b

Given m∠X:

Adjacent = b
Opposite = a
Hypotenuse = c

SinX= b CosX = a TanX= b
c c a

So the answer is B.

Attached is a picture of how I assigned the sides depending on the angle used.