Answer:
On 7.8 acres there are 31565.3 square meters
7.8 acres = 31565.3 m²
Explanation:
Conceptual analysis
Acre, square mile and square meter are area units, so their equivalences are in square units.
Known data
1 (mi)² = 640 acres
1 mi = 1609.34 m
Problem development
We know that 1 mile = 1609.34m, then: (1 mile)² = (1609.34m)²=(1609.34)²m²
We apply the known conversion factors to calculate the square meters (X) in 7.8 acres:

We eliminate acres and square miles (mi²) because they are in the numerator and denominator, so the answer is in square meters (m²)
X=31565.3 m²
On 7.8 acres there are 31565.3 square meters
7.8 acres = 31565.3 m²
Answer:
7*10^(-11) m.
Explanation:
the details are in the attached picture (the answer is marked with red).
The limbic system, which includes the hippocampus, the amygdala, the cingulate gyrus, the thalamus, the hypothalamus, the epithalamus, the mammillary body and other organs, many of which are of particular relevance to the processing of memory<span>. So I'd assume that it came from the limbic system, no?</span>
here's the solution,
The <em>radius</em> of the circle =<u> 3 km</u>
distance covered = <em>circumference</em> of the circle,
So, Circumference :
=》

=》

=》

(a). Distance covered by moving object is 18.84 km
(b). 0 km
now, Displacement of the object is 0 km, because displacement is the shortest distance from stating point to the destination, but the object returns back to the starting point, hence magnitude of displacement is 0.
This would be an example of active immunity