I believe it is because with a net you simply find the area, and measuring 2D shapes is far easier than 3D shapes.
Hope this helped!
- Z
Answer:
(a) 8.15
(b) 12.92
Step-by-step explanation:
Given: P = $3000, r = 0.085

Where
A is the Amount
P is the Principal
r is the rate
t is the time
(a) For the amount to double, A = 2 × P
A = 2 × $3000
A = $6000



Take
of both sides

But 
∴ 


t = 8.15
(b) For the amount to double, A = 3 × P
A = 3 × $3000
A = $9000



Take
of both sides

But 
∴ 


t = 12.92
-- 100% of the original number is ALL of it.
-- If it's increased by that amount, it becomes DOUBLE
(twice as much as) what it was originally.
The proper name of the quadrilateral is called Parallelograms