We are given a quadrilateral with one interior angle of $226^\circ$ and two exterior angles of $35^\circ$ and $42^\circ$. We are asked to find the size of the remaining exterior angle $f$.
2025/6/22
1. Problem Description
We are given a quadrilateral with one interior angle of and two exterior angles of and . We are asked to find the size of the remaining exterior angle .
2. Solution Steps
Let's denote the interior angles of the quadrilateral as .
We are given that one of the interior angles is . Let .
We are given two exterior angles: and .
The exterior angle and the interior angle at a vertex add up to .
Let the interior angle at one vertex be , and the exterior angle at that vertex be . Then
Let the interior angle at another vertex be , and the exterior angle at that vertex be . Then
The sum of the interior angles of a quadrilateral is .
There seems to be something wrong. It should have been a reflex angle of instead of an interior angle of . We can form a quadrilateral by extending the sides.
Let the interior angles be . The external angles are , and .
Therefore, , .
The interior angle at is . .
The sum of the angles in a triangle is .
We have , where are interior angles, and are external angles of a quadrilateral.
Another interpretation of the figure:
The figure looks like a triangle with one side extended.
So we can say that the sum of the angles and equals the exterior angle at the .
, this is the interior angle at the vertex. Therefore is an exterior angle.
Since is an exterior angle of the triangle, is not correct.
Let the missing angle f be such that the polygon consists of 4 angles. The interior angles of this polygon are . The sum of the interior angles of a 4-sided polygon is
3
6
0. Therefore, $145+134+138+F=360, F=360-417=-57$. The polygon must be non-convex.
Let's see. .
The exterior angle is . The reflex angle is
2
2
6. $f = 360 - 35 - 42 - 226$. Then $f = 57^\circ$.
The angles in the triangle are then , and angle f which corresponds to the angle with 226 on the other side.
If the triangle angles add up to , we would have the two non adjacent triangle angles
We know 35 + 42 =77 is one angle.
So f= 180 - 77=103
Then the exterior angle would be
Let's look for another way.
The exterior angle at the reflex angle vertex is
Since the sum of external angles is always , we have
.
Then f + is equal to something. We know 35 + 42= 77 and
Therefore the angle opposite to is , the interior is and .
The total external angles is 77+103+90
. So the interior is
7
7. Final Answer: The final answer is $\boxed{103}$
3. Final Answer
103