An engineer designed a new bridge and drew the scale drawing shown below. 6 Inches If the engineer used the scale 3 inch = 40 feet, how long is the actual bridge the engineer designed?

The bridge is 80 feet long

Step-by-step explanation:

We will use the ratio method to solve the question

∵ The engineer used the scale 3 inch = 40 feet

∴ The scale drawing is ⇒ 3 inche :  40 feet

∵ The drawing length of the bridge is 6 inches

→ By using the ratio method

→  inch :  feet

→  3      :  40

→  6      :  x

→ By using cross multiplication

∵ 3 × x = 6 × 40

∴ 3x = 240

→ Divide both sides by 3

∴ x = 80

∵ x represents the actual length of the bridge

∴ The bridge is 80 feet long

it would open into a square depending on the type of envelope i’m not sure about the second part

the solution of the equation is 2.23 ⇒ answer b

step-by-step explanation:

* lets revise the meaning of exponential function

- the form of the exponential function is y = ab^x, where a ≠ 0, b > 0 ,  

  b ≠ 1, and x is any real number

- it has a constant base b

- it has a variable exponent x

- to solve an exponential equation, take the log or ln of both sides,  

  and solve for the variable

* lets solve the problem

∵

- the base is 7 and the exponent is x

- insert ㏑ in both sides

∴

- use the rule

∴ x ㏑(7) = ㏑(77)

- to find x divide both sides by ㏑(7)

∴

* the solution of the equation is 2.23 to the nearest 2 decimal places