Answer:21
Step-by-step explanation: plug in 19 and 1
1x3 is 3 plus 19 is 21


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- BCD is an isosceles right triangle , right angled at D
- ABC is an equilateral triangle


❒ Sum of all angles is 180° , since it is an equilateral triangle all the three angles would be same





(Isosceles triangle)









Answer:
<h2>a = 16</h2>
Step-by-step explanation:
Look at the picture.
The formula of an area of a trapezoid is:

- bases
- height
We have:

Substitute:

<em>divide both sides by 8</em>

There are 25 species of trees, each with a known abundances. The question is how many possible ways to randomly select one tree there are.
We should calculate the number of combinations. Combinations, because we select item/s from a collection. In this case, when we select only one item, the combination is also a permutation. From set of n objects we select r. In our case: n=25, r=1.
The equation is: n!/r!(n-r)!= 25!/1!*24!=25*24!/24!=25
There are 25 different outcomes (events).