Answer:
21.27 meters.
Step-by-step explanation:
Please find the attachment.
Let H and h represent height of building and tree respectively.
We have been given that a person on the ground looks up at an angle of 28° and sees the top of a tree and the top of a building aligned. The tree is 20 m away from the person and the building is 60 m away from the person.
We know that tangent relates opposite side of a right triangle with its adjacent side.
[tex]\text{tan}=\frac{\text{Opposite}}{\text{Adjacent}}[/tex]
[tex]\text{tan}(28^{\circ})=\frac{H}{60}[/tex]
[tex]60\cdot \text{tan}(28^{\circ})=H[/tex]
[tex]60\cdot 0.531709431661=H[/tex]
[tex]H=31.90256589966\approx 31.90[/tex]
Similarly, we can find height of the tree.
[tex]\text{tan}(28^{\circ})=\frac{h}{20}[/tex]
[tex]20\cdot\text{tan}(28^{\circ})=h[/tex]
[tex]20\cdot 0.531709431661=h[/tex]
[tex]h=10.63418863322\approx 10.63[/tex]
[tex]H-h=31.90-10.63[/tex]
[tex]H-h=21.27[/tex]
Therefore, the difference in heights between the building and tree is 21.27 meters.