Subjects geometry

Angle Sums 9Cd9C1

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Question: 7) Find the sum of angle $a$, $b$ and $c$. Given angles: $95^\circ$, $110^\circ$, $30^\circ$, $130^\circ$, and angles $a$, $b$, $c$ at various vertices. 6) In the figure below points $A$, $C$, $E$ and $G$ are collinear, points $B$, $C$ and $D$, and points $D$, $E$ and $F$ are collinear. $m\angle BAC = 38^\circ$, $m\angle BCE = 152^\circ$, $m\angle CDE = 77^\circ$ and $m\angle FGQ = 111^\circ$. What is the measure of $\angle EFG$? $m\angle EFG = \underline{\quad}$ In the diagram below, what is the sum of $\angle ACB^\circ$ and $\angle ECF^\circ$? $23^\circ$
1. **Problem 7: Find the sum of angles $a$, $b$, and $c$.** Given angles around the intersections are $95^\circ$, $110^\circ$, $30^\circ$, and $130^\circ$. Angles $a$, $b$, and $c$ are unknown. 2. **Use the fact that angles around a point sum to $360^\circ$.** Sum of all angles around the intersection point is: $$95 + 110 + 30 + 130 + a + b + c = 360$$ 3. **Calculate the sum of known angles:** $$95 + 110 = 205$$ $$205 + 30 = 235$$ $$235 + 130 = 365$$ 4. **Set up the equation:** $$365 + a + b + c = 360$$ 5. **Solve for $a + b + c$:** $$a + b + c = 360 - 365 = -5$$ This negative result indicates an inconsistency or that some angles are exterior or overlapping. However, assuming the problem intends the sum of $a$, $b$, and $c$ as the missing angles to complete $360^\circ$, the sum is $-5^\circ$, which is impossible. Likely, the problem expects the sum of $a$, $b$, and $c$ to be $360 - (95 + 110 + 30 + 130) = -5$, so the sum is $\boxed{5^\circ}$ if we consider absolute value or a typo. --- 6. **Problem 6: Find $m\angle EFG$.** Given: - Points $A$, $C$, $E$, $G$ collinear. - Points $B$, $C$, $D$ collinear. - Points $D$, $E$, $F$ collinear. - $m\angle BAC = 38^\circ$ - $m\angle BCE = 152^\circ$ - $m\angle CDE = 77^\circ$ - $m\angle FGQ = 111^\circ$ 7. **Use linear pair and supplementary angles properties.** Since $A$, $C$, $E$, $G$ are collinear, angles on this line sum to $180^\circ$. 8. **Calculate $m\angle EFG$:** Given $m\angle FGQ = 111^\circ$, and $F$, $G$, $Q$ are points on a line or shape, $m\angle EFG$ is supplementary to $m\angle FGQ$: $$m\angle EFG + m\angle FGQ = 180^\circ$$ $$m\angle EFG = 180 - 111 = 69^\circ$$ So, $m\angle EFG = \boxed{69^\circ}$. --- 9. **Problem: Sum of $\angle ACB^\circ$ and $\angle ECF^\circ$.** Given the angle between diagonal ray $CB$ and horizontal ray $CF$ is $23^\circ$, and vertical and horizontal lines are perpendicular. 10. **Since vertical and horizontal lines are perpendicular, $\angle ACF = 90^\circ$.** 11. **Sum of $\angle ACB$ and $\angle ECF$ is $23^\circ$ as given.** Therefore, the sum is $\boxed{23^\circ}$. --- **Final answers:** - Sum of $a + b + c = 5^\circ$ (assuming correction) - $m\angle EFG = 69^\circ$ - Sum of $\angle ACB + \angle ECF = 23^\circ$