Answer:

Step-by-step explanation:
Let point
be the point where the straight line drawn from point
meets the straight line
, it is evident that
and
is similar given that both triangles share the same angle,
. Hence, the ratio of the sides of each triangle is the same. Specifically,
.
Performing cross multiplication yields
.
Perimeter of Rectangle: 2W + 2L
One L is the river so we have 3 sides
420m/3 = 140m
Area of Rectangle is WL
140×140= 19,600 Sq meters
I'm assuming you may have another mathematical system the teacher wants you to use. Yet, I get Area is 19,600 Sq meters
Step-by-step explanation:
x = father's age now
y = son's age now
x = 2y + 10
x - 20 = 5(y - 20) = 5y - 100
using the first in the second equation :
2y + 10 - 20 = 5y - 100
-10 = 3y - 100
90 = 3y
y = 30
x = 2y + 10 = 2×30 + 10 = 60 + 10 = 70
the father is now 70 years old, the son now 30 years old.
9900 because you divide 99000 by 10