SAT Math · Lines, angles, and triangles · medium
In a triangle, one exterior angle measures 135°. The two remote interior angles measure 4x° and (2x+15)°. What is the value of x?
In a triangle, one exterior angle measures . The two remote interior angles measure and . What is the value of ?
Answer and explanation
Answer: A: 20
By the exterior angle theorem, an exterior angle equals the sum of the two remote interior angles. So , which simplifies to and then , giving , choice A. Check: the remote interior angles are and , which add to . Choice B (22.5) comes from , forgetting to subtract 15. Choice C (67.5) is half of 135. Choice D (15) is the constant in the second angle. Don't forget the constant term when solving.
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