Tricky Question on Polygons Solved Fast: Avoid This Common Mistake in Sec 1 Math

When it comes to polygons, even confident Secondary 1 students can get tripped up by angle-related questions. This is especially true when the question involves more than one type of interior angle. If you are searching for help with a question on polygons, this is the right place to start.

Here’s a real question asked by a student on the platform:

Question:
Two of the interior angles of an n-sided polygon are 74° and 136°, and the remaining interior angles are 110° each. Find the value of n.

This question is a good test of your understanding of interior angles and the angle sum of polygons. It goes beyond simply applying a formula and requires a clear grasp of how to break down the problem step by step.

Instead of feeling stuck, the student received instant homework help through our on-demand homework help feature. The solution shared below comes from a real mentor-student chat and shows how guided support can clarify even the trickiest concepts.

Real mentors, Real-time answers

Bryan

how to solve?
hi i will explain
ok!
The sum of the interior angles of an n-sided polygon is given by the formula:

S=(n−2)×180
given the information
he sum of all interior angles can also be expressed as:

S=74 +136 +(n−2)×110
form the equation (n−2)×180 =74 +136 +(n−2)×110
from there you can solve it and n = 5
wait why is is (n-2)x110?
total there are n interior angles
excluding 74 and 136, you are left with n-2 interior angles that are 11
110*
ohhh ok ty I understand now!
welcome!

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