Answer:
the point is (3, 3) . . . . . . y = 3
Step-by-step explanation:
Write the point-slope equation of the line through the point you know. Then evaluate that equation for x=3 to see what the value of y is.
Point-slope form:
y = m(x -h) +k . . . . slope m through point (h, k)
y = -1/2(x -9) +0 . . . . line with slope -1/2 through point (9, 0)
For x=3, the value of y is ...
y = -1/2(3 -9) + 0 = -1/2(-6) = 3
The value of y is 3.
48. The surface area of a cylinder is given by
... A = 2πr² + 2πrh = 2πr(r+h)
For r = 13 mi and h = 7 mi, this becomes
... A = 2π(13 mi)(13 mi + 7 mi) = 520π mi²
The surface area of the cylinder is 520π mi² ≈ 1634 mi².
49. The surface area of a rectangular prism is
... A = 2(LW + H(L+W))
For L = 20 m, W = 10 m, H = 7 m, this becomes
... A = 2((20 m)(10 m) + (7 m)(20 m + 10 m)) = 2(200 m² + 210 m²) = 820 m²
The surface area of the prism is 820 m².
50. The formula is the same as for problem 48.
For r = 10 m and h = 13 m, this becomes
... A = 2π(10 m)(10 m + 13 m) = 460π m² ≈ 1445 m²
The surface area of the cylinder is 460π m² ≈ 1445 m².
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When calculations are repetitive, it is convenient to let a calculator or spreadsheet do them.
