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
Step-by-step explanation:
Using the formulas
A
=
π
r
2
C
=
2
π
r
Solving for
A
A
=
C
2
4
π
=
117
2
4
·
π
≈
1089.33601
cm²
A
≈
1089.34
cm²
Answer:
x = 15.3
x = 20.9
Step-by-step explanation:
sin(46) = 11/x
⇒ x = 11/sin(46) = 15.3
cos(55) = 12/x
⇒ x = 12/cos(55) = 20.9
x^2-9x-6=0
Use the quadratic formula to get (9+sqrt(105))/2 or (9-sqrt(105))/2
Answer:
y=-x+5 the y intercept is 5 and the slope is -1
Step-by-step explanation: