The area of study known as the history of mathematics is primarily an investigation into the origin of discoveries in mathematics and, to a lesser extent, an investigation into themathematical methods and notation of the past. ... Chinese mathematicsmade early contributions, including a place value system.
6 - the front, back, 2 sides, and top and bottom :)
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Answer:
<u><em>Measure of angle A is 27 7/9 degrees.</em></u>
Step-by-step explanation:
Lets call measure of angle A is <em><u>X-10</u></em>
Lets call measure of angle B is X
Lets call measure of angle D is 2.5X+20
We know that the sum of triangles add up to 180 degrees
X+X-10+2.5X+20=180
X=37 7/9
So measure of angle A is 27 7/9 degrees.
I hope this is right. :)
