Answer:
System of equations:
20x + 30y = 650
x + y = 25
Time underwater = 10 hours
Time at the surface = 15 hours
Step-by-step explanation:
Let x = time underwater at 20 km/h.
Let y = time on the surface at 30 km/h.
speed = distance/time
distance = speed * time
distance underwater: 20x
distance on the surface: 30y
total distance: 650
20x + 30y = 650
total time: x + y
total time: 25
x + y = 25
20x + 30y = 650
x + y = 25
20x + 30y = 650
-20x - 20y = -500
--------------------------------
10y = 150
y = 15
x + y = 25
x + 15 = 25
x = 10
11.8/2 = 5.9
5.9 squared is <span>34.81
34.81 multiplied by pi is </span>109.358840271
The equation of the circle is :
+
+ 6.4
+ 4.2
= 3.84
<h3>Meaning of a Circle</h3>
A circle is a loci or a continuous line that equidistant from the center to any point on the line. it drawn starting from a point and ending on that same point.
The equation of a circle is an equation used to find points on a circle so the circle can be drawn with accurate measurement. it can also be used to find the missing points.
In conclusion, The equation of the circle is :
+
+ 6.4
+ 4.2
= 3.84
Learn more about equation of a circle: brainly.com/question/1506955
#SPJ1