surface area (S) of a right rectangular solid is:
S = 2*L*W + 2*L*H + 2*W*H (equation 1)
where:
L = length
W = width
H = height
-----
you have:
L = 7
W = a
H = 4
-----
formula becomes:
S = 2*7*a + 2*7*4 + 2*a*4
simplify:
S = 14*a + 56 + 8*a
combine like terms:
S = 22*a + 56
-----
answer is:
S = 22*a + 56 (equation 2)
-----
to prove, substitute any value for a in equation 2:
let a = 15
S = 22*a + 56 (equation 2)
S = 22*15 + 56
S = 330 + 56
S = 386
-----
since a = 15, then W = 15 because W = a
go back to equation 1 and substitute 15 for W:
S = 2*L*W + 2*L*H + 2*W*H (equation 1)
where:
L = length
W = width
H = height
-----
you have:
L = 7
W = 15
H = 4
-----
equation 1 becomes:
S = 2*7*15 + 2*7*4 + 2*15*4
perform indicated operations:
S = 210 + 56 + 120
S = 386
-----
surface area is the same using both equations so:
equations are good.
formula for surface area of right rectangle in terms of a is:
S = 22*a + 56
-----
Hey there! I"m happy to help!
The interior angles of a triangle add up to 180. We have 2 angles that have a value of x, so 2x+138=180.
We subtract 138 from both sides.
2x=42
We divide both sides by 2
x=21.
Have a wonderful day! :D
For part A, if P is the center of that triangle, then PR and PT have the same length; therefore, triangle RPT is isosceles. For part B, by the definition of an incenter...if P is an incenter, then it is the place where all the angle bisectors meet. Therefore, angles SRP and PRT are congruent, as are angles STP and PTR. Since the vertex angle measures 64, then each of the base angles by the isosceles triangle theorem measure 58. Half of 58 makes the base angles within the smaller triangle measure 29. And if both of those measure 29, by the triangle angle-sum theorem, 180-29-29 = 122 And that's the measure of angle RPT. Eek.
Answer: 90 degrees
Step-by-step explanation:
Answer:
Now that his car is 5 years old, he would like to know whether the variability of gas mileage has changed. He recorded the gas mileage from his last eight fill-ups; these are listed here. Conduct a test at a 10% significance level to infer whether the variability has changed.
Step-by-step explanation:
