For this case we have the following equation:
 h (t) = at ^ 2 + v * t + h0
 Substituting values we have:
 h (t) = - 16 * t ^ 2 + 60 * t + 3
 We equate the equation to zero:
 -16 * t ^ 2 + 60 * t + 3 = 0
 We look for the roots of the polynomial:
 t1 = -0.04935053979258153
 t2 = 3.7993505397925817
 We are left with the positive root and round:
 t2 = 3.8 s
 Answer:
 t = 3.8 s
 option 3
        
             
        
        
        
Step-by-step explanation:
area of circle= πr²
3.14×7×7
153.86 is the required area
 
        
             
        
        
        
A² = c² - b²
a² = 21² - 13 ²
a² = 441 - 169
a² = 272
a = √272 = 16.49242 ≈ 16.49
Answer : D ) 16.49
        
                    
             
        
        
        
12=5x-13x-44
combine like terms
12 = -8x -44
add 44 to each side
12+44 = -8x
56= -8x
divide by -8 on each side
56/-8 = x
-7 =x