Step-by-step explanation:
The upstream speed is S / t₁, and the downstream speed is S / t₂.
If we say f is the speed of the fish in calm water, and r is the speed of the river, then:
f − r = S / t₁
f + r = S / t₂
If we say T is the time it takes to cross the river, then the speed perpendicular to the river is ℓ/T, the speed parallel to the river is r, and the overall speed is f.
Using Pythagorean theorem:
f² = (ℓ/T)² + r²
f² − r² = (ℓ/T)²
(f − r) (f + r) = (ℓ/T)²
(S / t₁) (S / t₂) = (ℓ/T)²
S² / (t₁ t₂) = (ℓ/T)²
(t₁ t₂) / S² = (T/ℓ)²
√(t₁ t₂) / S = T/ℓ
T = ℓ√(t₁ t₂) / S
Answer: C is the answer
Step-by-step explanation:
Answer:
42 square centimeters
Step-by-step explanation:
The total of sides FA and AB will be half the perimeter of the rectangle, or 14 cm. Since AB is 9 cm, that means FA is 5 cm.
EF is the difference between EF and FA, so is 11 cm -5 cm = 6 cm.
FC is the same 9 cm length as AB, so we have enough information about the trapezoid to use the area formula:
A = (1/2)(b1 +b2)h
A = (1/2)(9 cm +5 cm)(6 cm) = 42 cm^2
The area of the trapezium is 42 cm^2.
Answer:
B. -2
Step-by-step explanation:
All you have to do is look at 2 on the x axis and see where it lines up on the graph with the y axis. In this case, when you trace the line of 2 it matches up with -2 on the graph.
