advance problems arithmetic versus algebra

[kyrhocorum 6-olw]

Arithmetic

The house has an area of 200 sq.m. The shape of the house is square. What is the perimeter of the house?
Answer:
(square root of 200) x 4
56.568542494923801952

Algebra
The first shape has 25 sides.The second shape has 30 sides. The third shape has 35 sides. How many sides are there in the 15th. shape?
Answer
95
Which is harder?

[Pi=]

Arithmetic

The house has an area of 200 sq.m. The shape of the house is square. What is the perimeter of the house?
Answer:
(square root of 200) x 4

Algebra
The first shape has 25 sides.The second shape has 30 sides. The third shape has 35 sides. How many sides are there in the 15th. shape?
Answer
95
Which is harder?

Solution to both probems.

Arithmetic - Since the area is side squared and the area is 200 sq.m, take the square root to figure out the length of a side. Multiply by 4 to get perimeter, = (sqrt200)(4) = 56.blargh

Algebra - Since the common difference is +5, simply plug in. The formula for the sides would be : A sub n = a sub 1 + (n-1)d, plugging in =
A sub 15 = 25 + (15-1)5 = 25 +70 = 95.