A polygon<span> has as many interior </span>angles<span> as sides. An equilateral triangle has three equal 60 </span>degree angles<span>. The </span>sum<span> of the </span>angles<span> of this and any triangle is </span>180 degrees<span>.The </span>sum<span> of the four interior </span>angles<span> of a square is 360 </span>degrees<span>, which is the same for any quadrilateral.</span>
Answer:$1.32
Step-by-step explanation:
Step 1. Multiply 5 by y and you get 5y
Step 2. Multiply 5 by .4(2/5)
Step 3. Your equations will look like 5y+2=-13
Step 4. Subtract 2 from its self and -13
Step 5. Your equation will be 5y=-15
Step 6. Divide 5 from both sides
Step 7. Your answer is y=-3
Answer:
Step-by-step explanation:
The formula for determining the sum of the first n terms of an arithmetic sequence is expressed as
Sn = n/2[2a + (n - 1)d]
Where
n represents the number of terms in the arithmetic sequence.
d represents the common difference of the terms in the arithmetic sequence.
a represents the first term of the arithmetic sequence.
If a = 5, the expression for the sum of the first 12 terms is
S12 = 12/2[2 × 5 + (12 - 1)d]
S12 = 6[10 + 11d]
S12 = 60 + 66d
Also, the expression for the sum of the first 3 terms is
S3 = 3/2[2 × 5 + (3 - 1)d]
S3 = 1.5[10 + 2d]
S3 = 15 + 3d
The sum of the first 12 terms is equal to ten times the sum of the first 3 terms. Therefore,
60 + 66d = 10(15 + 3d)
60 + 66d = 150 + 30d
66d + 30d = 150 - 60
36d = 90
d = 90/36
d = 2.5
For S20,
S20 = 20/2[2 × 5 + (20 - 1)2.5]
S20 = 10[10 + 47.5)
S20 = 10 × 57.5 = 575