Answer: 
Step-by-step explanation:
You need to use the following formula that is used to find the area of a trapezoid:

Where "M"and "m" are the bases of the trapezoid and "h" is the height of the trapezoid.
Based on the information given in the exercise, you can identify that:

Knowing these values, you can substitute them into the formula:

Finally, you must evaluate in order to find its area. This is:

Answer:
1655
Step-by-step explanation:
Note the common difference d between consecutive terms of the sequence
d = - 1 - (- 4) = 2 - (- 1) = 5 - 2 = 8 - 5 = 3
This indicates the sequence is arithmetic with sum to n terms
=
[ 2a₁ + (n - 1)d ]
Here a₁ = - 4, d = 3 and n = 90, thus
=
[ (2 × - 4) + (89 × 3) ] = 45(- 8 + 267) = 45 × 259 = 1655
Answer:
C
Step-by-step explanation:
Calculate AC using Pythagoras' identity in ΔABC
AC² = 20² - 12² = 400 - 144 = 256, hence
AC =
= 16
Now find AD² from ΔACD and ΔABD
ΔACD → AD² = 16² - (20 - x)² = 256 - 400 + 40x - x²
ΔABD → AD² = 12² - x² = 144 - x²
Equate both equations for AD², hence
256 - 400 + 40x - x² = 144 - x²
-144 + 40x - x² = 144 - x² ( add x² to both sides )
- 144 + 40x = 144 ( add 144 to both sides )
40x = 288 ( divide both sides by 40 )
x = 7.2 → C
Answer:
x = 24
Step-by-step explanation:
18 + 0.5x = 12 +0.75 x
18 - 12 = 0.75 x - 0.5x
6 = 0.25 x
24 = x