Forming & Solving Equations (Edexcel IGCSE Maths A (Modular))

The pentagon being regular means the side lengths are all equal.

If the total perimeter of a regular pentagon with side length is cm, then:

1. Find the total perimeter in terms of by multiplying by 5

2. Set this equal to 100

This forms the equation .

True.

If the interior angles of an -sided polygon are given algebraically in terms of , you can calculate the size of as the total sum of the angles will always be .

E.g. for any hexagon (regular or irregular), the sum of its interior angles will always be .
So if the interior angles are in terms of , add them together and set equal to .

True.

You can use a 'show that' answer from part (a) to do part (b), even if you did not complete part (a) yourself.

If part (a) says to show that certain information leads to the equation , then you can use that equation in part (b) without having proved part (a)!

Answer the question in context means that your final answer should

• be related to the real-life situation in the question

• be written in sentences

• use words and phrases from the question

• state the correct units

• be rounded appropriately

The answer should not be, for example:

• (no explanation)

• "the length is bigger" (no context)