Sum Formula (n-2)×180°: Real-world Applications in Shopping & Money
Mathematics
Grade 7
15 questions
~30 mins
1 views0 downloads
About This Worksheet
A worksheet exploring the sum of interior angles in polygons using the formula (n-2)×180°, with contexts related to shopping and money.
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Sum Formula (n-2)×180°: Real-world Applications in Shopping & Money
Subject: MathematicsGrade: Grade 7
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Untitled Worksheet
Grade Grade 7
A
Introduction
Read the explanation below.
1.
The sum of the interior angles of a polygon with n sides can be calculated using the formula (n-2)×180°. This helps us find the total angles inside the shape. Understanding this is useful when designing shopping displays or packaging that involves polygonal shapes.
[2 marks]B
Fluency & Practice
Answer the following questions to practice calculating the sum of interior angles.
1.
Calculate the sum of interior angles of a hexagon.
[2 marks]2.
Find the total interior angles for a decagon.
[2 marks]3.
What is the sum of interior angles in a polygon with 9 sides?
[2 marks]4.
A pentagon has a total interior angle sum of how many degrees?
[2 marks]C
Problem Solving & Reasoning
Solve these multi-step problems involving polygons.
1.
A shopping display is shaped like an octagon. If the total interior angles sum to 1080°, how many sides does the polygon have? Show your working.
[3 marks]2.
A retailer designs a new package with a polygonal shape that has 12 sides. What is the sum of all its interior angles? Explain your calculation.
[3 marks]D
Real-world Applications
Answer these questions based on shopping and money scenarios.
1.
A shopping cart basket is modeled as a pentagon. If the sum of its interior angles is 540°, what is the number of sides if a customer wants to add an extra side to make a heptagon while keeping the same total angle sum? Show your reasoning.
[4 marks]2.
A display case is designed as a polygon with an unknown number of sides. If the sum of interior angles is 1800°, how many sides does the polygon have? Provide your calculation process.
[4 marks]E
Challenge & Extension
Tackle these advanced problems involving polygons and their interior angles.
1.
Design a polygonal shopping sign with 15 sides. Calculate the measure of each interior angle if the shape is regular. Show all working.
[3 marks]2.
A polygon has interior angles totaling 1980°. Determine the number of sides. Then, find the measure of each interior angle if the polygon is regular.
[4 marks]F
Mixed Review
Answer a variety of questions to review your understanding.
1.
A decagon is used in a decorative frame. If some angles are extended and the total interior angle sum becomes 1440°, how many sides does the original decagon have? Show your working.
[3 marks]2.
Calculate the interior angle sum of a polygon with 20 sides.
[2 marks]G
Error Analysis
Identify and correct the common mistakes in the following questions.
1.
A student calculates the interior angles of a hexagon as 120° each, then sums to 720°. Is this correct? If not, what mistake was made? Correct the calculation.
[3 marks]2.
A shape with 8 sides is claimed to have a total interior angle sum of 1080°. Is this accurate? Explain and correct if necessary.
[3 marks]Quick Actions
What is Remix?
Create a new worksheet based on this one. Change the grade level, topic, number of questions, or difficulty - then generate a fresh version.
- • Change grade level (Grade 6 → Grade 7)
- • Swap topics (Harry Potter → Macbeth)
- • Add more questions (10 → 15)
- • Adjust difficulty
Details
- Created
- 1/1/2026
- Updated
- 1/1/2026
- Type
- worksheet