# Diagonals of pentagon

Calculate the diagonal length of the regular pentagon:

a) inscribed in a circle of radius 12dm;

b) a circumscribed circle with a radius of 12dm.

a) inscribed in a circle of radius 12dm;

b) a circumscribed circle with a radius of 12dm.

## Correct answer:

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### You need to know the following knowledge to solve this word math problem:

**algebra**- expression of a variable from the formula
**planimetrics**- right triangle
- circle
- polygon
- area of a shape
- triangle
- diagonal
**goniometry and trigonometry**- sine
- cosine
- tangent

### Units of physical quantities:

### Grade of the word problem:

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