WHY must a heptagon add up to 900° (in pictures)
Because there are now 5 triangles in a heptagon and it must add up to `5times180°=900°`.
The heptagon can be made from 5 triangles.
Example 1
An equilateral heptagon will have 7 equal internal angles and would be
`900^circ/7=128.57^circ`
Each internal angle is 128.57°.
But the interior angles would still add up to 900°.
![](/images/user/base/Maths/Logarithms/Reference%20Tables/reference-log-table-1.4df6ee6.jpg)
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![](/images/user/base/Maths/Logarithms/Reference%20Tables/reference-anti-log-table-1.b0b0513.jpg)
![](/images/user/base/Maths/Logarithms/Reference%20Tables/reference-anti-log-table-2.f89189d.jpg)