The sides of a triangle are 9, 12, and 15 centimeters long. what is the angle between the 2 shortest sides?

Use this following formula to solve the problem
a² + b² - (2ab) cos C = c²

From the question, we can determine
a = 9
b = 12
c = 15
and the question is the angle C (angle between a and b)

Input the numbers between the formula
a² + b² - (2ab) cos C = c²
9² + 12² - (2 × 9 × 12) cos C = 15²
81 + 144 - 216 cos C = 225
225 - 216 cos C = 225
-216 cos C = 0
cos C = 0
∠C = 90°

Angle between the 2 shortest sides is 90°

Do the math. she originally had 50 dollars on her gift card and she had 12 dollars left on her gift card after she finished her shopping spree. if you subtract 50 minus 12 you get thirty eight dollars as your answer. so therefore, ciara spent 38 dollars total o