The sum of the first n terms in a geometric sequence given the first term (a1) and the common ratio (r) is calculated through the equation,
<span>Sn </span>= (<span><span><span>a1</span>(1−<span>r^n</span>) / (</span><span>1−r)
Substituting the known terms,
Sn = (20)(1 - (1/4)^4)) / (1 - 1/4)
Sn = 26.5625
Thus, the sum of the first four terms is 26.5625. </span></span>
Answer:
138 cm.
Step-by-step explanation:
So first, we find the S.A. of the front and back.
The diagram says the side length of the front is 3 cm. and 3 cm.
3x3=9. So then, the back is also 9 cm, 9+9=18.
Now to find the S.A.'s of the four sides, you have to see the side lengths of each of them. The side lengths are 3 and 10.
3x10=30. This means each of them is 30 cm.
30x4=120. 120 is the total surface area of the four sides.
To find the total surface area of the whole rectangle, you add all the surface areas.
120+18=138 cm. (Not squared, since it's surface area and not area.)
Answer: 1. HA cannot be a reason to show given triangles are congruent as it is not given that they have an acute angle common in both the triangles.
2. HL can be a reason to show given triangles are congruent as the triangles are right triangle with equal legs and hypotenuse.
3. SAS can be a reason to show given triangles are congruent as there are two congruent sides in both triangles and included angles ∠A=∠D=90° [right angle].
4. LA cannot be a reason to show given triangles are congruent as it is not given that they have an acute angle common in both the triangles.
5. AAS cannot be a reason to show given triangles are congruent as it is not given that they have two angles common in both the triangles.
6.SSS can be a reason to show given triangles are congruent as it is shown that all the sides of one triangle is congruent to the other.
HOPE THIS HELPS
