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Question

In a triangle, if angle $A = 30^\circ$ and angle $B = 45^\circ$, then what is the angle of C?

This question was previously asked in
RRB NTPC 2019 CBT 1 Question Paper (8-Mar-2021) (Shift 2)
The correct answer is
$105^\circ$

Solving for Triangle Angle C

The sum of the interior angles in any triangle is always $180^\circ$. This fundamental property can be represented by the formula:

$ \text{Angle A} + \text{Angle B} + \text{Angle C} = 180^\circ $

Applying the Angle Sum Theorem

We are given the measures of two angles:

  • Angle A = $30^\circ$
  • Angle B = $45^\circ$

Substitute these values into the formula:

$ 30^\circ + 45^\circ + \text{Angle C} = 180^\circ $

Calculating Angle C

First, sum the known angles:

$ 75^\circ + \text{Angle C} = 180^\circ $

Next, isolate Angle C by subtracting $75^\circ$ from both sides:

$ \text{Angle C} = 180^\circ - 75^\circ $

$ \text{Angle C} = 105^\circ $

Therefore, the measure of angle C is $105^\circ$.

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Similar Questions

  1. In $\triangle ABC$, $BD \perp AC$ at $D$ and $\angle DBC = 40^\circ$. $E$ is a point on $BC$ such that $\angle CAE = 37^\circ$. What is the measure of $\angle AEB$?
  2. In $\Delta ABC$, $BD \perp AC$ at D and $\angle DBC = 71^\circ$. E is a point on BC such that $\angle CAE = 17^\circ$. What is the measure of $\angle AEB$?
  3. In triangle ABC, bisector of $\angle\text{ABC}$ and $\angle\text{ACB}$ meet at O. If $\angle\text{BAC} = 60^\circ$, then find the measure of $\angle\text{BOC}$.
  4. In $\Delta\text{XYZ}$, $\text{XY} = 12\text{ cm}$ and $\text{YZ} = 18\text{ cm}$. $\text{XW}$, the angle bisector of $\text{YXZ}$, meets $\text{YZ}$ at $\text{W}$, such that $\text{YW} : \text{WZ}$ is $4 : 5$. Find the length of the third side of the triangle.
  5. In $\Delta\text{PQR}$, $\text{QR}$ is extended up to $\text{S}$ so that $\text{RS} = \text{RP}$. If $\angle\text{PRQ} = 70^\circ$ and $\angle\text{QPS} = 110^\circ$ then find the measure of $\angle\text{PQS}$.
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  7. In $\Delta PQR$, QR is extended up to S, so that RS = RP. If $\angle RPQ = 55^\circ$ and $\angle PRS = 110^\circ$, then find the measure of $\angle PQS$.
  8. The sides of a triangle are 44 cm, 33 cm, and 55 cm. What is its area? (in $cm^2$)
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Important Questions from Triangles

  1. What is the circumcenter of the triangle ABC?

  2. What is the centroid of the triangle ABC?

  3. What is the foot of the altitude from the vertex A of the triangle ABC?

  4. In ΔABC, D is a point on BC such that ∠ADB = 2∠DAC, ∠BAC = 70° and ∠B = 56°. What is the measure of ∠ADC?

  5. In ΔABC, ∠A = 66° and ∠B = 50 °. If the bisectors of ∠B and ∠C meet at P, then ∠BPC – ∠PCA = ?

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