Selina solutions

Selina solutions

Selina solutions

Grade 7

CHAPTERS

3. Fractions (Including Problems)

4. Decimal Fractions (Decimals)

5. Exponents (including Laws of Exponents)

6. Ratio and Proportion (Including Sharing in a Ratio)

7. Unitary Method (including Time and Work)

11. Fundamental Concepts (Including Fundamental Operations)

12. Simple Linear Equations (Including Word Problems)

13. Set Concepts (Some Simple Divisions by Vedic Method)

14. Lines and Angles (Including Construction of angles)

17. Symmetry (Including Reflection and Rotation)

18. Recognition of Solids (Representing 3-D in 2-D)

Q13) Are the following pairs of angles supplementary?

(i) 139^{\circ}\ \ \ and\ 39^{\circ}

(ii) 26^{\circ}59'\ \ and\ 153^{\circ}1'

(iii) \frac{3}{10}\ \ of\ a\ right\ angle\ and\ \frac{4}{15}of\ two\ right\ angles\

(iv) 2x^{\circ}+65^{\circ}\ \ and\ 115^{\circ}-2x^{\circ}

Solution:

(i) 139° and 39° : No, these are not supplementary angles as their sum is not 180° (139° + 39° = 178°)

(ii) 26° 59’ and 153° 1’: Yes, there are supplementary angles as their sum is 180° (26° 59’ + 153° 1’ = 180°)

(iii) (3/10) of a right angle and 4/15 of two right angles

⇒ (3/10) of 90° and 4/15 of 180°

⇒ 27° and 48°: No, there are not supplementary angles as their sum is not 180° (27° + 48° = 75°)

(iv) 2x° + 65° and 115° - 2x° : Yes there are supplementary angles as their sum is 180° (2x + 65° + 115° - 2x° = 65° + 115° = 180°)

Still have questions? Our expert teachers can help you out

Book a free class nowFractions (Including Problems)

Exponents (including Laws of Exponents)

Ratio and Proportion (Including Sharing in a Ratio)

Unitary Method (including Time and Work)

Fundamental Concepts (Including Fundamental Operations)

Simple Linear Equations (Including Word Problems)

Set Concepts (Some Simple Divisions by Vedic Method)

Lines and Angles (Including Construction of angles)

Symmetry (Including Reflection and Rotation)

Recognition of Solids (Representing 3-D in 2-D)

Q13) Are the following pairs of angles supplementary?

(i) 139^{\circ}\ \ \ and\ 39^{\circ}

(ii) 26^{\circ}59'\ \ and\ 153^{\circ}1'

(iii) \frac{3}{10}\ \ of\ a\ right\ angle\ and\ \frac{4}{15}of\ two\ right\ angles\

(iv) 2x^{\circ}+65^{\circ}\ \ and\ 115^{\circ}-2x^{\circ}

Solution:

(i) 139° and 39° : No, these are not supplementary angles as their sum is not 180° (139° + 39° = 178°)

(ii) 26° 59’ and 153° 1’: Yes, there are supplementary angles as their sum is 180° (26° 59’ + 153° 1’ = 180°)

(iii) (3/10) of a right angle and 4/15 of two right angles

⇒ (3/10) of 90° and 4/15 of 180°

⇒ 27° and 48°: No, there are not supplementary angles as their sum is not 180° (27° + 48° = 75°)

(iv) 2x° + 65° and 115° - 2x° : Yes there are supplementary angles as their sum is 180° (2x + 65° + 115° - 2x° = 65° + 115° = 180°)

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