<h3>
Answer: x = 5</h3>
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Explanation:
The square marker indicates a 90 degree, or right angle.
The two smaller angles (3x and 75) both combine to the larger 90 degree angle. That's what it means when they say we have complementary angles.
Add up the smaller angles, set the sum equal to 90, and solve for x.
3x+75 = 90
3x+75-75 = 90-75 ....... subtracting 75 from both sides
3x = 15
3x/3 = 15/3 ..... divide both sides by 3
x = 5
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If x = 5, then 3x = 3*5 = 15
Then we can see that 15+75 = 90 to help check our answer.
