The document defines and provides examples of different types of triangles and quadrilaterals. It discusses isosceles, right-angled, acute-angled, obtuse-angled, equilateral triangles as well as rhombus, square, rectangle, parallelogram. It also covers the angle sum properties of triangles and quadrilaterals and includes examples of finding unknown angles in various figures.

1. Triangles and Quadrilaterals
Created by : Evangeline Cardenas-Manalang
A Practice Review for Primary 5
● Naming the types of triangles and quadrilaterals
● Finding the unknown marked angle/s.

2. Name the kinds of Triangles
and Quadrilaterals

3. A triangle in which angles opposite the
equal sides are equal.
Isosceles triangle

4. A four-sided figure which opposite sides are
parallel and all sides equal.
Rhombus

5. A triangle that has one right angle.
Right-angled triangle

6. All four sides are equal in length and all the angles
are right angles.
square

7. A triangle that has three acute angles.
Acute-angled triangle

8. A quadrilateral that has two pairs of parallel sides
and all the angles are right angles.
rectangle

9. A triangle that has one obtuse angle
Obtuse-angled triangle

10. A quadrilateral which has two pairs of parallel sides
but does not have right angles.
Parallelogram

11. A triangle which all sides have equal lengths.
Equilateral triangle

12. Concept:
● In a triangle,the sum of all the
angles is equal to 180⁰
● In a quadrilateral, the sum of
all the angles is equal to 360⁰

13. Find the unknown marked
angles

14. The following figures are not drawn to
scale.Find the unknown marked angles.

15. 180⁰ - 54⁰ = 126⁰
126⁰ ÷ 2 = 63⁰
⎳a = ⎳b = 63⁰

16. 180⁰ - 90⁰ - 25⁰ = 65⁰
⎳a = 65⁰
or
90⁰ - 25⁰ = 65⁰
⎳a = 65⁰

17. 180⁰ ⁰ ÷ 3 = 60⁰
⎳a = 60⁰

18. 360⁰- 149 ⁰ - 150 ⁰ = 61⁰
⎳a = 61⁰
1
180⁰ - 61⁰ = 119⁰
119⁰ ÷ 2 = 59.5⁰
⎳b = 59.5⁰
1

19. ⎳a = 360⁰ - 325 ⁰ = 35⁰
1 ⎳b = 180⁰ - 35 ⁰ - 109⁰ = 36⁰
⎳c = ⎳d = 180⁰ - 109⁰ = 71⁰
⎳e = 109⁰ ( vertically opposite angles )

20. ⎳a = 360⁰ - 304 ⁰ = 56⁰
⎳b = 180 ⁰ - 57 ⁰ = 123⁰
⎳c = 360⁰ - 34 ⁰ = 326⁰

21. ⎳a = 59 ⁰
⎳b = 121⁰
*Opposite angles are equal.

22. ⎳a = 180⁰ - 99⁰ = 81⁰
⎳b = 180⁰ - 63⁰ = 117⁰

23. ⎳a = 91⁰
● In rhombus opposite angles
are equal.

24. ⎳a = ⎳b
360⁰ - 67⁰ - 59⁰ = 234⁰
234⁰ ÷ 2 = 117⁰
⎳a = ⎳b = 117⁰

25. 23 April 2019