Download App

Triangles — Maths STD 9 — Question

Gujarat BoardEnglish MediumSTD 9MathsTriangles1 Mark
✓

Answer

  1. $\frac{3}{2}\text{x}^\circ$
    Solution:

    From figure,
    $\angle\text{DOC}=180^\circ-\angle\text{AOD}$ (Both are Supplementary)
    $\Rightarrow\angle\text{DOC}=180^\circ-3\text{y}^\circ$
    Also, $\angle\text{ACB}=180^\circ-\angle\text{A}-\angle\text{B}$
    $\Rightarrow\angle\text{ACB}=180^\circ-\text{x}^\circ-2\text{x}^\circ=180^\circ-3\text{x}^\circ$
    And $\angle\text{ACD}=180^\circ-\angle\text{ACB}$
    $=180^\circ-(180^\circ-3\text{x}^\circ)$
    $\Rightarrow\angle\text{ACD}=3\text{x}^\circ$
    Now, in $\triangle\text{OCD}$
    $\angle\text{DOC}+\angle\text{OCD}+\angle\text{D}=180^\circ$
    $180^\circ-3\text{y}^\circ+3\text{x}^\circ+\text{y}^\circ=180^\circ$ $\big[\angle\text{OCD}=\angle\text{ACD}\big]$
    $\Rightarrow2\text{y}^\circ=3\text{x}^\circ$
    $\Rightarrow\text{y}=\frac{3}{2}\text{x}^\circ$

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Explore more

More "M.C.Q" from Triangles→Triangles — all question types→Maths STD 9 question papers→Gujarat Board STD 9 question papers→Gujarat Board question paper generator→

Similar questions

In the following, write the correct answer.
In $\triangle\text{PQR},$ if $\angle\text{R}>\angle\text{Q}$ then:
→
Thales belongs to the country:
  1. India.
  2. Egypt.
  3. Greece.
  4. Babylonia.
→
The Parallel sides of a trapezium are ‘a’ and ‘b’ resp. The line joining the mid-points of its non-parallel sides will be.
→
A hemispherical bowl is made of steel, 0.25cm thick. If the inner radius of the bowl is 3.25cm, then the outer curved surface area of the bowl is:
→
A frequency polygon is constructed by plotting frequency of the class interval and the
→
An irrational number between $\sqrt{2}$ and $\sqrt{3}$ is
→
If $\text{x}=\big(7+4\sqrt{3}\big)$ then $\Big(\text{x}+\frac{1}{\text{x}}\Big)=?$
→
A linear equation in two variables x and y is of the form ax = by + c = 0, where:

  1. $\text{a}\neq0,\ \text{b}\neq0$

  2. $\text{a}\neq0,\ \text{b}=0$

  3. $\text{a}=0,\ \text{b}\neq0$

  4. $\text{a}=0,\ \text{c}=0$

→
The equation of a line parallel to y-axis and 4 units to the right of origin is:
→
The product of two irrational number is:
  1. always irrational.
  2. always rational.
  3. always an integer.
  4. sometimes rational and sometimes irrational.
→