Answer:
The river is 3.15 feet deep.
Step-by-step explanation:
First let's recognize what we need to find: the depth of the river
We know last year the river was 4.2 feet deep, but it dropped 25%. This means we also need to find how much it dropped. To find this, we need to know what 25% of 4.2 is. Write an equation for this.
y = 25% of 4.2
y = 0.25 • 4.2
y = 1.05
This means that the river dropped 1.05 feet. To know its depth now, we need to subtract 1.05 from 4.2. Write an equation for this.
d = 4.2 - 1.05
d = 3.15
The river is 3.15 feet deep.
Hope this helps!
Answer:
The algebraic expression is 80d
Step-by-step explanation:
Maria's earnings per day = $80
Number of days= d
Total earnings for d days:
80d
Where,
80 is earnings per day
d is number of days
The algebraic expression is 80d
Algebraic equation is
y= 80d
Where
y= total income earned in d days
The expression is different from am equation because of the equal to sign(=)
Step 
<u>Find the length of the side MN</u>
we know that
Applying the Pythagorean Theorem

Solve for MN

in this problem

Substitute in the formula above



Step 
<u>Find the value of cos (M)</u>
we know that
in the right triangle MNL


Substitute



therefore
The answer is
The value of cos(M) is equal to 