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Which property was used to simplify the expression? 3c+9 +4c=3c+4c+9

The triangle shown has a hypotenuse with a length of 13 feet. the measure of angle a is 20 degrees. and the measure of angle b is 70 degrees. which of the following is closest to the length, in feet, of line segment ac? no need to use a calculator to find the trig numbers. each function is listed below. 4.4 5 12.2 35.7

David leaves his house to go to school. he walks 200 meters west and 300 meters north. how far is david from his original starting point?