Answer:
64ft
Step-by-step explanation:
a+b/2xh
17+9=16
16/2=8
8x8=64ft
The best way to multiply complicated problems mentally* is to break them into chunks.
Start with 20 times 8 to get 160, and then 8 times 5 to get 40. Add these together to get 200. 200 times 3 is 600, and 20 times 200 is 4000. Add these together to get your final answer, 4600.
In other words 8 x 20 + 8 x 5 = 200 200 x 3 + 200 x 20 = 4600
*I assumed you meant mentally, because otherwise you'd just multiply longhand, multiplying two of the three numbers and then multiplying their product with the third.
Change in altitude:
42,000 - 18,000 = 24,000 feet
Rate of change = 24,000 feet / 12 minutes = 2,000 feet per minute
Because the plane was going down, the rate of change would be negative.
The rate would be -2,000 feet per minute.
Answer:
The answer is in the picture. I hope it is helpful.
