Combined perimeter of two rectangles

For shapes such as squares, rectangles and circles, you can use formulas to calculate the perimeter when you only know one or two dimensions. When you need to find the perimeter of a shape made up of a combination of other shapes, it may appear at first that you are not given enough dimensions. However, you can use the given dimensions to calculate the other necessary dimensions and then find the perimeter of the entire shape

SQUARES AND CIRCLES

125 Dolphins

Step-by-step explanation:

The number of dolphins varied linearly with the number of fish.

The number of dolphins = D

The number of fish = F

Hence:

D ∝ F

D = kF

When 400 fish were present 250 dolphins appeared

Solving for k

250 = 400k Equation 1

Also

when 300 fish were present, 200 dolphins appeared.

200 = 300k Equation 2

So: we find k = Constant of Proportionality

250 = 400k Equation 1

200 = 300k Equation 2

We Subtract Equation 2 from Equation 1

50 = 100k

k = 50/100

k = 1/2

How many dolphins would appear if 250 fish were present?

D = kF

D = 1/2 × 250

D = 125 Dolphins