Answer: 87°
Step-by-step explanation:
Sum ange of a supplementary triangle is 180°
Therefore, to get the measure of the largest angle, we add the angles together and equate to 180 to get the value of x first.
18x - 7 + 12x + 9 + 4x = 180°
34x + 2 = 180°
34x = 180 - 2
34x = 178
Divide through by 34
x = ¹⁷⁸/₃₄
x = 5.24.
Now substitute for x to get the measure of the largest angle.
i. 18(5.24) - 7 = 87.32,° to the nearest degree = 87°
ii. 12(5.24) + 9 = 71.88°, to the nearest degree = 72°
iii. 4(5.24) = 20.96, to the nearest degree = 21°
The largest angle is 87°
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