Answer: see proof below
<u>Step-by-step explanation:</u>
Given: A + B + C = π and cos A = cos B · cos C
scratchwork:
A + B + C = π
A = π - (B + C)
cos A = cos [π - (B + C)] Apply cos
= - cos (B + C) Simplify
= -(cos B · cos C - sin B · sin C) Sum Identity
= sin B · sin C - cos B · cos C Simplify
cos B · cos C = sin B · sin C - cos B · cos C Substitution
2cos B · cos C = sin B · sin C Addition
Division
2 = tan B · tan C

<u>Proof LHS → RHS</u>
Given: A + B + C = π
Subtraction: A = π - (B + C)
Apply tan: tan A = tan(π - (B + C))
Simplify: = - tan (B + C)

Substitution: = -(tan B + tan C)/(1 - 2)
Simplify: = -(tan B + tan C)/-1
= tan B + tan C
LHS = RHS: tan B + tan C = tan B + tan C 
Answer:
D
Step-by-step explanation:
I took the quiz :)
Answer:
2.83
Step-by-step explanation:
just round to the nearest hundredth
34 tens + 20 tens = ?
1 ten = 10 ones or 10.
34 + 20 = 54
54 tens
34 tens + 20 tens = 54 tens
54 × 10 = 540
34 tens + 20 tens = ?
34 tens + 20 tens = 54 tens
34 tens + 20 tens = 540
Answer:
Speed of car B is 33 km/h and speed of car A is 
Step-by-step explanation:
Let speed of car B be
km/h
Speed of car A is 12 km/h more than car B.
Therefore,
Speed of car A =
km/h
Distance = Speed × Time
Distance travelled by car A in 4 hours =
km =
km
Distance travelled by car B in 4 hours =
km
Also, cars A and B are 312km apart after 4 hours.

Speed of car B is 33 km/h and speed of car A is 