The sum of all of the exterior angles of any regular polygon is 360 (I'm assuming by decagon you mean a regular dodecagon).
Because the total has to be 360, and a decagon has 10 sides, you divide 360 by 10 to get each exterior angle.
360 ÷ 10 = 36, so each exterior angle of a decagon is 36 degrees.
She has 45% of the original amount left
<h3>Ratio and proportions</h3>
Fractions are written as a ratio of two integers
Given the following
Initial amount. = ∈4000
Amount given to her sister = 1/4 * 4000 = 1000
Amount given to her brother = 40% of 3000 = 1200
Amount left = 4000 - (1000+1200)
Amount left = ∈1800
Determine the percentage left
x * 4000 = 1800
x = 1800/4000
x = 0.45
x = 45%
Hence she has 45% of the original amount left
Learn more proportion here: brainly.com/question/19994681
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Answer:
Expanded, the answer would be 10b + 40
Step-by-step explanation:
Just multiply 8 to 2b and 8
