Answer:
11. AEB/BEC
12. BCE
13. BEC
14. BE
15. B
16. A = 60°
17. YES
18. NO
19. 10 cm
Explanation:
Let's carefully use the information given to answer clear the questions asked.
11. A right angle are angles that are 90°
Right angle are mostly represented with a tiny box at a perpendicular poing
From the drawn triangle there, two right angles would be:
-AEB
-BEC
12. An acute (small) angle Is an angle that is less than 90°
From the triangle give, there are 5 acutes angles. But let's pick one
-BCE
13. An exterior angle of a triangle is equal to the sum of two interior angles of that triangle.
For TRIANGLE ABE, the sum of two internal angles ( 30° and 60°) = 90° BEC (exterior angle)
- BEC
14. A side common to ∆ABE and ∆BEC is BE.
15- A vertex Is a point where two or more lines or curves meet.
Acommon vertex to ∆ABE and ∆BEC = point B
16. An angle common to ∆ABE and ∆ABC = angle A
= 60°
17. YES
An equilateral triangle is a triangle with three equal sides.
An Isosceles triangle is one with two equal sides.
Hence, An EQUILATERAL TRIANGLE is also an ISOSCELES TRIANGLE.
18. NO
An Isosceles triangle can not be an equilateral triangle because only it's two sides are the same.
19. If the perimeter of an Equilateral triangle with 3 sides is 30.
Each side would be:
= 30/3
= 10cm
Math is fun