In order to find the volume of a triangular pyramid, you must use the formula (abh)/6. Therefore, I believe the answer is 12 (if [a = a] [b = h] and [c = b]).
Answer:
X= 30-4r/-6
Step-by-step explanation:
1. Move the 9 to the other side. (21+9=30)
2. subtract the 4r and move it to the other side (-6x=21-4r)
3. divide both sides by -6
