Answer:
- x = 67.5°
- x = 39°
Step-by-step explanation:
1. Shown are the measures of three angles that, together, make up a full circle. The total of angle measures in a circle is 360°, so you have ...
... 90° + x + 3x = 360°
... 4x = 270° . . . . . . . . . . collect terms, subtract 90°
... x = 270°/4 = 67.5°
2. There are at least 3 different ways you can go at this, all based on the values of angles in a parallelogram.
- the sum of all angles in a parallelogram is 360°
- opposite angles are equal (congruent)
- adjacent angles are supplementary
I choose to use the second approach, setting the measure of the upper left angle equal to that of the angle at lower right.
... 3x -15 = 2x +24
... x -15 = 24 . . . . . . . subtract 2x
... x = 39 . . . . . . . . . . add 15
_____
Comment on the degree symbol in this problem
In the first problem, x is shown without any symbol indicating the sort of measure that is to be used for the angle. It is therefore appropriate to use radians as the angle measure. There are 2π radians in a circle, and π/2 radians in a right angle, so the correct answer is x = 3π/8.
In the second problem, the presence of numbers like -15 and +24 suggest that the angle measures are in degrees, but no degree symbol is present. The relation used for solving the problem holds regardless of the angle the values -15 and +24 are supposed to represent. However, finishing out the problem, we find that opposite angle measures come to 78 and 102, values that only make sense if the numbers are numbers of degrees. In short, the question is incorrectly posed: it should say (3x-15)° or (3x-15°), depending on whether the answer is desired without or with the degree symbol attached.