A 20­ft ladder is leaning against a house. The bottom of the ladder is 3 ft from the house. To the nearest tenth of a foot, about how high does the top of the ladder reach?

 19.8 ft

Step-by-step explanation:

Use the Pythagorean Theorem formula to solve for how high the top of the ladder reach.  

The formula says  a^2 + b^2 = c^2

Where a and b are the two legs and  C is the hypotenuse.

In this situation, the hypotenuse will be length of the ladder , and either  a or b will be the length of the ladder from the building or the length of how long the ladder.

a will be 3 ,  and c will be 20. Input in the values  into the formula and solve for b.

3^2 + b^2 = 20^2

9 + b^2 = 400

-9              -9

 b^2 = 391  

    b =

  b  = 19.77371   round to the nearest tenth is ,  19.8

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step-by-step explanation: