Evaluate 8.1p + 7.9r when p=7 and r=8
1 answer:
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Answer:
6.2832 square units (rounded off to four decimal values)
Step-by-step explanation:
Area of a semicircle = × π × r²
r (radius) = 2 units
For our semicircle the area = × π × 2² = 6.28318530718 square units
Or 6.2832 square units (rounded off to four decimal values)
Answer:
1. 516 ppm; 2. 561 ppm
Step-by-step explanation:
1. CO₂ increase at old rate
Time = 2100 - 2010 = 90 years
Increase in CO₂ = 90 yr × (1.4 ppm/1 yr) = 126 ppm
CO₂ in 2010 = 390 + 126 = 516 ppm
At the old rate, the CO₂ concentration in 2100 will be 516 ppm.
2. CO₂ increase at new rate
Time = 2100 - 2010 = 90 years
Increase in CO₂ = 90 yr × (1.9 ppm/1 yr) = 171 ppm
CO₂ in 2010 = 390 + 171 = 561 ppm
At the new rate, the CO₂ concentration in 2100 will be 561 ppm.
